SERINA THERAPEUTICS, INC., 10-K filed on 3/24/2025
Annual Report
v3.25.1
Cover - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Mar. 20, 2025
Jun. 30, 2024
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Current Fiscal Year End Date --12-31    
Document Period End Date Dec. 31, 2024    
Document Transition Report false    
Entity File Number 1-38519    
Entity Registrant Name Serina Therapeutics, Inc.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 82-1436829    
Entity Address, Address Line One 601 Genome Way    
Entity Address, Address Line Two Suite 2001    
Entity Address, City or Town Huntsville    
Entity Address, State or Province AL    
Entity Address, Postal Zip Code 35806    
City Area Code (256)    
Local Phone Number 327-9630    
Title of 12(b) Security Common Stock, par value $0.0001 per share    
Trading Symbol SER    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] false    
Entity Shell Company false    
Entity Public Float     $ 38.4
Entity Common Stock, Shares Outstanding   9,932,215  
Documents Incorporated by Reference [Text Block]
None
    
Entity Central Index Key 0001708599    
Document Fiscal Year Focus 2024    
Amendment Flag false    
Document Fiscal Period Focus FY    
v3.25.1
Audit Information
 12 Months Ended
Dec. 31, 2024
Audit Information [Abstract]  
Auditor Firm ID 215
Auditor Name Frazier & Deeter, LLC
Auditor Location Tampa, Florida
v3.25.1
Consolidated Balance Sheets - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Current assets:    
Cash and cash equivalents $ 3,672 $ 7,619
Prepaid expenses and other current assets 2,004 0
Total current assets 5,676 7,619
Property and equipment, net 501 573
Right of use assets - operating leases 461 666
Right of use assets - finance leases 86 110
TOTAL ASSETS 6,724 8,968
Current liabilities:    
Accounts payable 744 580
Accrued expenses 1,429 583
Other current liabilities 193 250
Total current liabilities 2,366 1,413
Warrant liability 3,582 0
Convertible promissory notes, at fair value 0 2,983
Operating lease liabilities, net of current portion 268 461
Finance lease liabilities, net of current portion 0 1
TOTAL LIABILITIES 6,216 4,858
Commitments and contingencies (Note 12)
Redeemable convertible preferred stock:    
Redeemable convertible preferred stock, $0.01 par value; 10,000 shares authorized; zero and 3,438 shares issued and outstanding at December 31, 2024 and 2023, respectively; Liquidation preference of zero and $36,982 at December 31, 2024 and 2023, respectively 0 36,404
Stockholders’ equity (deficit):    
Common stock, $0.0001 par value, 40,000 shares authorized; and 9,422 and 2,410 shares issued and outstanding at December 31, 2024 and 2023, respectively 1 0
Additional paid-in capital 44,958 883
Accumulated deficit (44,318) (33,177)
Total Serina Therapeutics, Inc. stockholders’ equity (deficit) 641 (32,294)
Noncontrolling interest (133) 0
Total stockholders’ equity (deficit) 508 (32,294)
TOTAL LIABILITIES, REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY(DEFICIT) $ 6,724 $ 8,968
v3.25.1
Consolidated Balance Sheets (Parenthetical) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Statement of Financial Position [Abstract]    
Temporary equity, par or stated value per share (in usd per share) $ 0.01 $ 0.01
Temporary equity, shares authorized (in shares) 10,000 10,000
Temporary equity, shares issued (in shares) 0 3,438,000
Temporary equity, shares outstanding (in shares) 0 3,438,000
Liquidation Preference $ 0 $ 36,982
Common stock, par or stated value per share (in usd per share) $ 0.0001 $ 0.0001
Common stock, shares authorized (in shares) 40,000,000 40,000,000
Common stock, shares, issued (in shares) 9,422,000 2,410,000
Common stock, shares, outstanding (in shares) 9,422,000 2,410,000
v3.25.1
Consolidated Statements of Operations - USD ($)
shares in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Revenues [Abstract]    
Total revenues $ 56 $ 3,153
OPERATING EXPENSES    
Research and development 7,480 2,388
General and administrative 9,624 3,894
Total operating expenses 17,104 6,282
Loss from operations (17,048) (3,129)
OTHER INCOME (EXPENSE), NET    
Interest expense (526) (558)
Fair value inception adjustment on convertible promissory note 0 2,240
Change in fair value of convertible promissory notes (7,017) 5,356
Change in fair value of warrants 13,156 1,077
Other income, net 228 283
Total other income, net 5,841 8,398
NET (LOSS) INCOME (11,207) 5,269
Net loss attributable to noncontrolling interest 66 0
NET (LOSS) INCOME ATTRIBUTABLE TO SERINA THERAPEUTICS, INC. $ (11,141) $ 5,269
NET (LOSS) INCOME PER COMMON SHARE:    
BASIC (in usd per share) $ (1.51) $ 2.36
DILUTED (in usd per share) $ (1.51) $ 0.73
WEIGHTED-AVERAGE NUMBER OF COMMON SHARES OUTSTANDING:    
BASIC (in shares) 7,359 2,235
DILUTED (in shares) 7,359 7,351
License revenues    
Revenues [Abstract]    
Total revenues $ 0 $ 3,000
Grant revenues    
Revenues [Abstract]    
Total revenues $ 56 $ 153
v3.25.1
Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity/(Deficit) - USD ($)
$ in Thousands
Total
Juvenescence Limited
Common Stock
Common Stock
Juvenescence Limited
Additional Paid-In Capital
Additional Paid-In Capital
Juvenescence Limited
Accumulated Deficit
Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2022 3,323,000              
Beginning balance at Dec. 31, 2022 $ 35,442              
Redeemable Convertible Preferred Stock                
Issuance of common stock upon conversion of preferred stock (in shares) 115,000              
Issuance of common stock upon conversion of preferred stock $ 962              
Ending balance (in shares) at Dec. 31, 2023 3,438,000              
Ending balance at Dec. 31, 2023 $ 36,404              
Beginning balance (in shares) at Dec. 31, 2022     2,167,000          
Beginning balance at Dec. 31, 2022 (37,778)   $ 0   $ 668   $ (38,446) $ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Issuance of common stock upon exercise of stock options (in shares)     243,000          
Issuance of common stock upon exercise of stock options 15   $ 0   15      
Issuance of common stock to AgeX stockholders and conversion of AgeX-Serina Note upon consummation of Merger 175       175      
Stock-based compensation 25       25      
Net income (loss) 5,269           5,269  
Ending balance (in shares) at Dec. 31, 2023     2,410,000          
Ending balance at Dec. 31, 2023 $ (32,294)   $ 0   883   (33,177) 0
Redeemable Convertible Preferred Stock                
Issuance of common stock upon conversion of preferred stock (in shares) (3,438,000)              
Issuance of common stock upon conversion of preferred stock $ 36,404              
Ending balance (in shares) at Dec. 31, 2024 0              
Ending balance at Dec. 31, 2024 $ 0              
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Issuance of common stock upon exercise of stock options (in shares) 195,000   195,000          
Issuance of common stock upon exercise of stock options $ 12   $ 0   12   0  
Issuance of stock (in shares)     3,438,000 500,000        
Issuance of stock 36,404 $ 5,392 $ 1   36,403 $ 5,392    
Issuance of common stock upon conversion of AgeX-Serina Note (in shares)     2,501,000          
Issuance of common stock to AgeX stockholders and conversion of AgeX-Serina Note upon consummation of Merger 961   $ 0   961      
Issuance of common stock upon exercise of Post-Merger Warrants (in shares)     378,000          
Issuance of common stock upon exercise of Post-Merger Warrants 6,360       6,360      
Deemed dividend from issuance of warrants (18,501)       (18,501)   0  
Gain on Sale of Subsidiary to Juvenescence 10,786       10,853     (67)
Stock-based compensation 2,595       2,595      
Net income (loss) (11,207)           (11,141) (66)
Ending balance (in shares) at Dec. 31, 2024     9,422,000          
Ending balance at Dec. 31, 2024 $ 508   $ 1   $ 44,958   $ (44,318) $ (133)
v3.25.1
Consolidated Statements of Cash Flows - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
OPERATING ACTIVITIES:    
Net (loss) income $ (11,207) $ 5,269
Adjustments to reconcile net (loss) income to net cash used in operating activities:    
Depreciation and amortization 194 90
Non-cash lease expense 227 174
Non-cash interest expense on convertible promissory note 164 558
Amortization of debt issuance costs 345 0
Stock-based compensation 2,595 25
Fair value inception adjustment on convertible promissory note 0 (2,240)
Change in fair value of convertible promissory notes 7,017 (5,356)
Change in fair value of warrants (13,156) (1,077)
Changes in operating assets and liabilities:    
Grant receivable 65 0
Prepaid expenses and other current assets (1,906) 16
Accounts payable (1,661) 393
Accrued expenses 400 (140)
Operating lease liabilities (214) (188)
Net cash used in operating activities (17,137) (2,476)
INVESTING ACTIVITIES:    
Purchase of property and equipment (22) (504)
Net cash used in investing activities (22) (504)
FINANCING ACTIVITIES:    
Proceeds from the issuance of common stock and warrants to Juvenescence 5,000 0
Drawdown on loan facilities from Juvenescence 3,043 0
Cash and restricted cash acquired in connection with the Merger 337 0
Proceeds from the exercise of stock options 12 15
Proceeds from the exercise of Post-Merger Warrants by Juvenescence 4,988 0
Proceeds from the issuance of convertible promissory notes 0 10,100
Principal repayment on loan facilities to Juvenescence (133) 0
Principal repayments on finance lease liabilities (35) (48)
Net cash provided by financing activities 13,212 10,067
NET CHANGE IN CASH AND CASH EQUIVALENTS (3,947) 7,087
CASH AND CASH EQUIVALENTS:    
At beginning of the year 7,619 532
At end of the year 3,672 7,619
SUPPLEMENTAL SCHEDULE OF NONCASH FINANCING AND INVESTING ACTIVITIES:    
Property and equipment purchases payable as of December 31 0 44
Right of use asset acquired in exchange for operating lease liabilities $ 0 $ 755
Conversion of convertible promissory notes and warrants issued 0 1,137,000
Issuance of common stock upon conversion of Preferred Stock $ 36,404 $ 0
Merger and issuance of common stock upon consummation of Merger on March 26, 2024 961 0
Deemed dividend from issuance of warrants 18,501 0
Derecognition of Post Merger and Incentive Warrants liability upon exchange transaction (1,799) 0
Issuance of common stock warrants upon exchange transaction 1,407 0
Issuance of warrants upon exercise of Post-Merger warrants 1,372 0
Extinguishment of debt upon sale of subsidiary $ 10,786 $ 0
v3.25.1
Organization, Basis of Presentation and Liquidity
 12 Months Ended
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Organization, Basis of Presentation and Liquidity Organization, Basis of Presentation and Liquidity
Serina Therapeutics, Inc. was incorporated as AgeX Therapeutics, Inc. in January 2017 in the state of Delaware. On March 26, 2024, AgeX Therapeutics, Inc. (“AgeX”) completed a merger transaction in accordance with the terms and conditions of the Agreement and Plan of Merger and Reorganization, dated as of August 29, 2023 (the “Merger Agreement”), by and among AgeX, Canaria Transaction Corporation, an Alabama corporation and a wholly owned subsidiary of AgeX (“Merger Sub”), and Serina Therapeutics, Inc., an Alabama corporation (“Legacy Serina”), pursuant to which Merger Sub merged with and into Legacy Serina, with Legacy Serina surviving the merger as a wholly owned subsidiary of AgeX (the “Merger”). Additionally, on March 26, 2024, AgeX changed its name from “AgeX Therapeutics, Inc.” to “Serina Therapeutics, Inc.”. Unless otherwise stated or the context otherwise requires, together with its subsidiaries, "Serina" or the "Company"). See Note 3, Recapitalization, for the accounting for the Merger.
Following the consummation of the Merger, the business previously conducted by Legacy Serina became the business conducted by the Company, which is now a clinical-stage biotechnology company developing Legacy Serina’s drug product candidates. The Company’s headquarters are located in Huntsville, Alabama (Legacy Serina’s headquarters).
The Company is a clinical-stage biotechnology company developing a pipeline of wholly-owned drug product candidates to treat neurological diseases and pain. The Company’s POZ drug delivery technology is designed to enable certain existing drugs and novel drug candidates to be modified in a way that may provide an increase in efficacy and safety of the resulting polymeric drug conjugate. The Company’s proprietary POZ technology is based on a synthetic, water soluble, low viscosity polymer called poly(2-oxazoline). The Company’s POZ technology is engineered to provide greater control in drug loading and more precision in the rate of release of attached drugs delivered via subcutaneous injection.
The therapeutic agents in the Company’s product candidates are typically well-understood and marketed drugs that are effective but are limited by pharmacokinetic (PK) profiles that can include toxicity, side effects and short half-life. The Company believes that by using POZ technology, drugs with narrow therapeutic windows can be designed to maintain more desirable and stable levels in the blood. The Company believes that POZ technology can be applied to small molecules, proteins, antibody drug conjugates, and other classes of molecules.
Prior to the closing of the Merger, any assets of AgeX other than certain “Legacy Assets” were transferred into a recently formed subsidiary of AgeX, UniverXome Bioengineering, Inc. (“UniverXome”). UniverXome assumed (i) any outstanding indebtedness of AgeX to Juvenescence Limited (“Juvenescence”), which was secured by the assets contributed to UniverXome, (ii) most of the Company’s contracts with third parties, other than certain designated contracts and any contracts that were terminated before the Merger, and (iii) all other liabilities of the Company in existence as of the effective time of the Merger (other than certain transaction expenses related to the Merger). On December 23, 2024, the Company entered into a Stock Purchase Agreement (the “Stock Purchase Agreement”) with Juvenescence, pursuant to which Juvenescence purchased all of the outstanding shares of UniverXome. See Note 5, Related Party Transactions for details.
Liquidity and Going Concern
In addition to general economic and capital market trends and conditions, the Company’s ability to raise sufficient additional capital to finance its operations from time to time will depend on a number of factors specific to the Company’s operations such as operating expenses and progress in out-licensing its technologies and development of its product candidates.
The unavailability or inadequacy of financing to meet future capital needs could force the Company to modify, curtail, delay, or suspend some or all aspects of planned operations. Sales of additional equity securities could result in the dilution of the interests of its stockholders. The Company cannot assure that adequate financing will be available on favorable terms, if at all.
The Company recognized a net loss of $11.1 million for the year ended December 31, 2024. The Company used $17.1 million in net cash from operating activities for the year ended December 31, 2024 and has historically incurred losses from operations and expects to continue to generate negative cash flows as the Company implements its business plan.
Management believes that its cash and cash equivalents of $3.7 million as of December 31, 2024, along with the $5 million of cash proceeds received from Juvenescence in January 2025 pursuant to the Agreement signed with Juvenescence on November 26, 2024 (See Note 7, Stockholders’ Equity/(Deficit) for details), will be used to fund Company operations but are not expected to be sufficient to satisfy the Company’s anticipated operating and other funding requirements for the twelve months from the issuance of these consolidated financial statements. Management has based its estimate of the funds needed to finance Company operations on assumptions that may prove to be wrong, and available capital resources could be exhausted sooner than expected. As such, there is substantial doubt about the Company’s ability to continue as a going concern.
The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, technical risks associated with the successful research, development and manufacturing of therapeutic candidates, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, and the ability to secure additional capital to fund operations. Therapeutic drug candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts will require significant amounts of additional capital, adequate personnel, and infrastructure. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize revenue from product sales. The Company expects to largely rely on raising capital from equity investors for funding its operations. Some funding is expected to be obtained through licensing agreements or other arrangements with commercial entities.
As a result of recurring losses from operations and recurring negative cash flows from operations, there is substantial doubt regarding the Company’s ability to maintain liquidity sufficient to operate its business within one year of the issuance date of its consolidated financial statements included in this Report. If sufficient capital is not available, the Company would be required to delay, limit, reduce, or terminate its product development or future commercialization efforts or grant rights to develop and market therapeutic candidates to other entities. There can be no assurance that the Company will be able to raise additional funds or that the terms and conditions of any future financings will be workable or acceptable to the Company or its shareholders. The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classifications of liabilities that might be necessary should the Company be unable to continue as a going concern.
v3.25.1
Summary of Significant Accounting Policies
 12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies Summary of Significant Accounting Policies
Principles of consolidation
The consolidated financial statements include the accounts of the Company and its subsidiaries in which the Company has a controlling financial interest. For consolidated entities where the Company has less than 100% of ownership, the Company records net loss attributable to noncontrolling interest on the consolidated statement of operations equal to the percentage of the ownership interest retained in such entities by the respective noncontrolling parties. The noncontrolling interest is reflected as a separate element of stockholders’ equity (deficit) on the Company’s consolidated balance sheets. Any material intercompany transactions and balances have been eliminated upon consolidation.
The Company assesses whether it is the primary beneficiary of a variable interest entity (“VIE”) at the inception of the arrangement and at each reporting date. This assessment is based on its power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and the Company’s obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. If the entity is within the scope of the variable interest model and meets the definition of a VIE, the Company considers whether it must consolidate the VIE or provide additional disclosures regarding its involvement with the VIE. If the Company determines that it is the primary beneficiary of the VIE, the Company will consolidate the VIE. This analysis is performed at the initial investment in the entity or upon any reconsideration event. For entities the Company holds as an equity investment that are not consolidated under the VIE model, the Company will consider whether its investment constitutes a controlling financial interest in the entity and therefore should be considered for consolidation under the voting interest model.
The Company had five subsidiaries: Legacy Serina and UniverXome, which are wholly-owned subsidiaries, and ReCyte Therapeutics, Inc. (“ReCyte”), Reverse Bioengineering, Inc. (“Reverse Bio”), and NeuroAirmid Therapeutics, Inc. (“NeuroAirmid”). Prior to the Merger, on March 26, 2024, pursuant to the Merger Agreement, the Company contributed all of its stock in Reverse Bio and ReCyte, along with substantially all of the assets (other than the stock of NeuroAirmid) of the Company to UniverXome. In exchange for the contribution of those assets, UniverXome assumed certain liabilities, including all of the Company’s indebtedness to Juvenescence. UniverXome owns 94.8% of the outstanding capital stock of
ReCyte. ReCyte owns certain pre-clinical research and development assets involving stem cell-derived endothelial and cardiovascular related progenitor cells for the treatment of vascular disorders and ischemic conditions. The Company owned 100% of the outstanding capital of Reverse Bio through UniverXome. Reverse Bio owns assets involved in partial cellular reprogramming using its iTR™ technology with the intent to revert aged or diseased cells to a healthy and functional state. Following the Merger, the Company is primarily focused on developing Legacy Serina’s product candidates which are described elsewhere in this Report.
NeuroAirmid is jointly owned by the Company and certain researchers from the University of California and was organized to pursue certain cell therapies, focusing initially on Huntington’s Disease. The Company owns 47.5% of the outstanding capital stock of NeuroAirmid. The Company consolidates NeuroAirmid despite not having majority ownership interest as it has the ability to influence decision making and financial results through contractual rights and obligations as per Accounting Standards Codification (“ASC”) 810, Consolidation. On March 27, 2024, the Board of Directors of the Company formed a special committee for the purpose of exploring strategic alternatives for the business, assets and/or stock of UniverXome, Reverse Bio, ReCyte and NeuroAirmid.
On December 23, 2024, following the Stock Purchase agreement with Juvenscence, the Company sold all outstanding shares of UniverXome for a nominal cash payment and deconsolidated UniverXome and underlying subsidiaries, ReCyte and Reverse Bio. See Note 5, Related Party Transactions for details.
Revision of prior period financial statements
A revision was made to correct the accounting for the recapitalization resulting from the Merger. The adjustment recorded increased additional paid-in capital by $19.8 million with a corresponding decrease to accumulated deficit as of the Merger date. An adjustment was also made to retrospectively reduce the par value of common stock to $0.0001 per share with a corresponding increase to additional paid-in capital. See Note 3, Recapitalization for details. In accordance with Staff Accounting Bulletin No. 99, Materiality, management has concluded that the adjustments are not material to its previously issued financial statements for the periods noted below. Management corrected these out-of-period adjustments in the current period within the consolidated balance sheets and consolidated statements of redeemable convertible preferred stock and stockholders' equity/(deficit) as of December 31, 2024. The following tables summarize the impact of each of the previous reporting periods impacted (amounts reflected in thousands).

A summary of the revisions as of December 31, 2023 is as follows:

Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Common Stock
$25 $(25)$— 
Additional paid-in capital$858 $25 $883 

A summary of the revisions as of March 31, 2024 is as follows:

Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Additional paid-in capital$— $19,803 $19,803 
Accumulated deficit$(28,389)$(19,803)$(48,192)

A summary of the revisions as of June 30, 2024 is as follows:

Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Additional paid-in capital$6,821 $19,803 $26,624 
Accumulated deficit$(23,185)$(19,803)$(42,988)

A summary of the revisions as of September 30, 2024 is as follows:
Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Additional paid-in capital$8,000 $19,803 $27,803 
Accumulated deficit$(21,775)$(19,803)$(41,578)
Financial statement reclassification
Certain account balances from prior periods have been reclassified in these consolidated financial statements to conform to current period classifications. Accounts payable and accrued expenses, previously presented as one line item on the consolidated balance sheet, are now presented separately given the materiality of the balances. The current portion of operating and finance lease liabilities were also reclassified to other current liabilities. Additionally, the non-cash interest expense on convertible promissory note, previously combined with accrued expenses in the operating activities section of the consolidated statement of cash flows, is now presented separately within operating activities. These reclassifications had no effect on the reported results of operations or financial position.
Use of estimates
The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and (ii) the reported amounts of revenues and expenses during the reporting period, in each case with consideration given to materiality. Significant estimates and assumptions which are subject to significant judgment include those related to assumptions used to value stock-based awards and liability classified warrants. Actual results could differ materially from those estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected.
Concentration of credit risk and other risks and uncertainties
Financial instruments that potentially subject the Company to concentrations of risk consist principally of cash equivalents. The Company maintains its cash deposits in Federal Deposit Insurance Corporation (“FDIC”) insured financial institutions and may at times hold investments at Securities Investor Protection Corporation (“SIPC”) insured broker-dealers.
The balances in these accounts may be in excess of FDIC and SIPC insured limits. At December 31, 2024 and 2023, cash and cash equivalents deposits in excess of FDIC limits were nominal and zero, respectively, and investments and deposits in excess of SIPC limits were $2.9 million and $7.3 million, respectively.
Product candidates developed by the Company and its subsidiaries will require approvals or clearances from the United States Food and Drug Administration (“FDA”) or foreign regulatory agencies prior to commercial sales. There can be no assurance that any of the product candidates being developed or planned to be developed by the Company or its subsidiaries will receive any of the required approvals or clearances. If regulatory approval or clearance were to be denied or any such approval or clearance was to be delayed, it would have a material adverse impact on the Company.
Fair value measurements of financial instruments
The Company has adopted ASC Topic 820, Fair Value Measurement, for certain financial instruments measured as fair value on a recurring basis. ASC Topic 820 defines fair value, establishes a framework for measuring fair value in accordance with accounting principles generally accepted in the United States, and expands disclosures about fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. ASC Topic 820 establishes a three-tier fair value hierarchy which prioritizes the inputs used in measuring fair value.
The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (level 1 measurements) and the lowest priority to unobservable inputs (level 3 measurements).
The three levels of inputs that may be used to measure fair value are as follows:
•Level 1: Quoted prices in active markets for identical assets or liabilities.
•Level 2: Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets with insufficient volume or infrequent transactions (less active markets), or model-derived valuations in which all significant inputs are observable or can be derived principally from or corroborated with
observable market data for substantially the full term of the assets or liabilities. Level 2 inputs also include non-binding market consensus prices that can be corroborated with observable market data, as well as quoted prices that were adjusted for security-specific restrictions.
•Level 3: Unobservable inputs to the valuation methodology are significant to the measurement of the fair value of assets or liabilities. Level 3 inputs also include non-binding market consensus prices or non-binding broker quotes that we were unable to corroborate with observable market data.
The Company has elected to measure the convertible promissory notes at fair value on a recurring basis. Changes in fair value are recorded in other income, net, on the consolidated statements of operation . Interest accrued on the notes is reflected in interest expense on the consolidated statement of operations.
Cash and cash equivalents
Cash and cash equivalents include unrestricted cash and all highly liquid instruments with original maturities of three months or less at the date of purchase. Cash equivalents consist primarily of amounts invested in money market accounts.
Property and equipment, net
Property and equipment are carried at cost less accumulated depreciation. The costs of additions and betterments are capitalized and expenditures for repairs and maintenance are expensed as incurred. When items of property and equipment are sold or retired, the related costs and accumulated depreciation are removed from the accounts and any gain or loss is included in the consolidated statements of operations. Depreciation of property and equipment is provided utilizing the straight-line method over the range of lives used of the respective assets, which is 3 - 10 years.
Leases
The Company determines if an arrangement is a lease at inception. Leases are classified as either finance or operating, with classification affecting the pattern of expense recognition in the consolidated statements of operations. The Company recognizes right-of-use (“ROU”) assets and lease liabilities for leases with terms greater than twelve months in the consolidated balance sheet.
ROU assets represent an entity’s right to use an underlying asset during the lease term and lease liabilities represent an entity’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. If the lease agreement does not provide an implicit rate in the contract, the lessee uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives. For such purposes, the lease term applied may include options to extend or terminate the lease when it is reasonably certain that the Company or a subsidiary will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term.
The Company has elected to combine lease and non-lease components as a single component. Operating leases are recognized on the consolidated balance sheet as ROU lease assets, current lease liabilities, and non-current lease liabilities. Fixed lease payments are included in the calculation of the lease balances, while variable costs paid for certain operating and pass through costs are excluded. The Company's finance leases are not material.
Intangible assets, net
Intangible assets, consisting primarily of acquired in-process research and development (“IPR&D”) with alternative future use and patents, are stated at acquired cost, less accumulated amortization. Amortization expense is computed using the straight-line method over the estimated useful life of 10 years. The Company's intangible assets were acquired as a result of the merger closing between Age-X and Serina and were sold in connection with the sale of UniverXome to Juvenescence in December 2024. Amortization expense was $0.1 million for the year ended December 31, 2024.
Impairment of long-lived assets
The Company assesses the impairment of long-lived assets whenever events or changes in circumstances indicate that such assets might be impaired and the carrying value may not be recoverable. If events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable and the expected undiscounted future cash flows attributable to the asset are less than the carrying amount of the asset, an impairment loss, equal to the excess of the carrying value of the
asset over its fair value, is recorded. There has been no impairment of long-lived assets for the accounting periods presented.
Accounting for warrants
The Company determines the accounting classification of warrants it issues, as either liability or equity, by first assessing whether the warrants meet liability classification in accordance with ASC 480-10, Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity, then in accordance with ASC 815-40, Accounting for Derivative Financial Instruments Indexed to, and Potentially Settled in, a Company’s Own Stock. Under ASC 480, warrants are considered liability classified if the warrants are mandatorily redeemable, obligate the Company to settle the warrants or the underlying shares by paying cash or other assets, or warrants that must or may require settlement by issuing a variable number of shares. If warrants do not meet liability classification under ASC 480-10, the Company assesses the requirements under ASC 815-40, which states that contracts that require or may require the issuer to settle the contract for cash are liabilities recorded at fair value, irrespective of the likelihood of the transaction occurring that triggers the net cash settlement feature. If the warrants do not require liability classification under ASC 815-40, and in order to conclude equity classification, the Company also assesses whether the warrants are indexed to its common stock and whether the warrants are classified as equity under ASC 815-40 or other applicable U.S. GAAP. After all relevant assessments, the Company concludes whether the warrants are classified as liability or equity. Liability classified warrants are recorded at fair value upon issuance and subsequently remeasured to fair value each reporting period until settlement with all changes in fair value recorded in the consolidated statements of operations. Equity classified warrants are recorded at fair value upon issuance and are not subsequently remeasured. See Note 5, Related Party Transactions and 6, Fair Value Measurements, for additional information regarding warrants.
Redeemable convertible preferred stock
The Company recorded redeemable convertible preferred stock at fair value upon issuance, net of any issuance costs. As of December 31, 2023, the Company's preferred stock that was redeemable in circumstances not within the Company’s control was classified outside of permanent equity. The redeemable preferred stock was converted into common stock on March 26, 2024 upon consummation of the Merger.

Revenue recognition
License revenues
The Company's license revenue relates to a non-exclusive license agreement entered into with Pfizer, Inc. in 2023 that was determined to be within the scope of ASC 606, Revenue From Contracts with Customers. As consideration for the agreement, the Company received an upfront payment and is eligible to receive future payments upon achievement of certain milestones as well as royalties on future sales of products developed using the licensed technology. As the Company's performance obligations were substantially completed upon transfer of the license, the upfront payment was recognized as revenue when earned. Milestone payments were not included in the initial transaction price as it was probable that a significant reversal of cumulative revenue would occur due to the uncertainty in achievement of such milestones. The milestone payments will be recognized as revenue when achievement of the specified milestones is probable. Royalty payments will be recognized as revenue when earned.

License revenues for the years ended December 31, 2024 and 2023, were zero and $3.0 million, respectively. Refer to Note 10, License Revenue for details.
Grant revenues
The Company receives government grants that reimburse the Company for certain allowable costs for funded projects. Grant revenue is recognized in the consolidated statement of operations on a systematic basis over the period in which the Company recognizes qualified research and development costs that grant is intended to compensate and there is reasonable assurance that the Company will meet the terms and conditions of the grant.

Grant revenues for the years ended December 31, 2024 and 2023 were not material.
Research and development expense
Research and development costs are expensed as they are incurred and primary consist of cost incurred for the development of product candidates and drug discovery efforts, which include personnel costs consisting of salaries, benefits and equity-based compensation expense; expenses incurred under agreements with consultants and contract organizations that conduct research and development activities on the Company's' behalf; costs related to production of preclinical and clinical
materials, including fees paid to contract manufacturers; laboratory and vendor expenses related to the execution of preclinical studies and planned clinical trials; and laboratory supplies and equipment used for internal research and development activities. The Company continually evaluates new product opportunities and engages in intensive research and product development efforts. Research and development expenses include both direct costs tied to a specific contract or grant, and indirect costs. Research and development expenses incurred and reimbursed by grants from third parties or governmental agencies, if any and as applicable, approximate the respective revenues recognized in the consolidated statements of operations.
General and administrative expense
General and administrative expenses consist primarily of personnel costs, and other expenses for outside professional services, including legal, recruiting, audit and accounting, and facility related costs not otherwise included in research and development expenses. Personnel costs consist of salaries, benefits and equity-based compensation expense for personnel in executive and other administrative functions.
Income taxes
Income taxes are provided in accordance with ASC Topic 740, which prescribes the use of the asset and liability method, whereby deferred tax asset or liability account balances are calculated at the balance sheet date using current tax laws and rates in effect. Valuation allowances are established when necessary to reduce deferred tax assets when it is more likely than not that a portion or all of the deferred tax assets will not be realized. ASC 740 guidance also prescribes a recognition threshold and a measurement attribute for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For benefits to be recognized, a tax position must be more-likely-than-not sustainable upon examination by taxing authorities. Deferred taxes represent the future tax return consequences of those differences, which will either be taxable or deductible when the assets and liabilities are recovered or settled. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which the differences are expected to be recovered or settled.
The Company only recognizes tax benefits from an uncertain tax position if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate resolution. To date, the Company has not recognized such tax benefits in its financial statements.
Stock-based compensation expense
The Company provides share-based payments in the form of stock options and restricted stock awards. For awards only subject to service conditions, the Company uses the straight-line attribution method for recognizing compensation expense over the requisite service period, which is generally the vesting period of the award. Compensation expense is recognized on awards ultimately expected to vest. Forfeitures are recorded when they occur.

The Company estimates the fair value of stock option awards and restricted stock awards on the grant date using a Black-Scholes option pricing model.
Basic and diluted net earnings (loss) per share attributable to common stockholders
The Company follows the two-class method when computing net loss per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net loss per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. The Company’s redeemable convertible preferred stock contractually entitles the holders of such shares to participate in dividends but does not contractually require the holders of such shares to participate in losses of the Company.
Basic earnings (loss) per share (“EPS”) of common stock is computed by dividing net income (loss) available to common stockholders (numerator) by the weighted average number of shares of common stock outstanding (denominator) during the period.
Diluted EPS gives effect to all dilutive potential common shares outstanding during the period using the treasury stock method for stock options and warrants and the if-converted method for redeemable convertible preferred stock and convertible promissory notes. In computing diluted EPS, the average stock price for the period is used to determine the number of shares assumed to be purchased from the exercise of stock options and/or warrants. Diluted EPS excludes all dilutive potential shares if their effect is anti-dilutive.
Segment reporting
Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the Chief Operating Decision Maker (the “CODM”), the Chief Executive Officer, in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating and reporting segment in the United States.
Recently adopted accounting pronouncements
In November 2023, the FASB issued Accounting Standards Update ("ASU") 2023-07, Segment Reporting (Topic 280)— Improvements to Reportable Segment Disclosures, which improves segment disclosure requirements, primarily through enhanced disclosure requirements for significant segment expenses. The improved disclosure requirements apply to all public entities that are required to report segment information, including those with only one reportable segment. The Company adopted as of January 1, 2024. There was no impact on the Company’s reportable segments identified and additional required disclosures have been included in Note 13.
In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740)—Improvements to income Tax Disclosures, under which entities must consistently categorize and provide greater disaggregation of information in the rate reconciliation. They must also further disaggregate income taxes paid. ASU 2023-09 enhances annual income tax disclosures to address investor requests for more information about the tax risks and opportunities present in an entity’s worldwide operations. The Company will adopt this standard as of January 1, 2025, adoption is not expected to have a material impact on the consolidated financial statements.
Recently issued accounting pronouncements not yet adopted
In March 2024, the FASB issued ASU 2024-02, Codification Improvements—Amendments to Remove References to the Concepts Statements. ASU 2024-02 removes various references to the FASB’s Concepts Statements from the FASB’s Codification. The Concepts Statements are non-authoritative guidance issued by the FASB that provide the objectives, qualitative characteristics and other concepts that govern the development of accounting principles by the FASB. The ASU indicates that the goal of the amendments is to simplify the Codification and distinguish between nonauthoritative and authoritative guidance (since, unlike the Codification, the concepts statements are nonauthoritative). This ASU is effective for the Company beginning January 1, 2025 and is not expected to have a material impact on the consolidated financial statements.
In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses to improve disclosures by providing more detailed information about the types of expenses in commonly presented expense captions. The guidance is effective for annual reporting periods beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the effect this standard will have on its consolidated financial statements and related disclosures.
v3.25.1
Recapitalization
 12 Months Ended
Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]  
Recapitalization Recapitalization
As described in Note 1, Legacy Serina merged with Merger Sub on March 26, 2024 with Legacy Serina surviving the merger as a wholly owned subsidiary of AgeX. The Merger was accounted for as a reverse recapitalization and Legacy Serina was considered the accounting acquirer for financial reporting purposes. This determination was based on the facts that, immediately following the Merger: (i) Legacy Serina stockholders own a substantial majority of the voting rights; (ii) Legacy Serina designated a majority of the initial members of the board of directors of the combined company; (iii) Legacy Serina’s executive management team became the management team of the combined company, and (iv) the combined company intends to primarily focus on developing Legacy Serina’s product candidates, and will not continue to develop AgeX’s product candidates.
Accordingly, for accounting purposes, the Merger was treated as the equivalent of Legacy Serina issuing stock to acquire the net assets of AgeX. As a result of the Merger, the Company recorded the assets and liabilities of AgeX at their
acquisition-date fair value, which approximated carrying value. The historical financial statements being presented prior to the Merger are those of Legacy Serina. Historical common and preferred shares of Legacy Serina have been retrospectively restated based on the exchange ratio of 0.97682654 (the “Exchange Ratio”). Additionally, the par value of common stock was retrospectively adjusted to reflect the par value ($0.0001) of the outstanding AgeX common shares with an offset recorded in additional paid-in capital.
At the effective time of the Merger, each outstanding share of Legacy Serina capital stock (after giving effect to the automatic conversion of all shares of Legacy Serina preferred stock into shares of Legacy Serina common stock or held or owned by AgeX or any subsidiary of AgeX or of Legacy Serina and any dissenting shares) was converted into the right to receive 0.97682654 shares of AgeX common stock. See table below representing the shares outstanding immediately following the effective time of the Merger.
Total AgeX shares outstanding prior to Merger2,500,612
Shares issued to Legacy Serina stockholders5,913,277
Total shares outstanding8,413,889
In addition, the Company assumed the Legacy Serina 2017 Stock Option Plan, and each outstanding and unexercised option and warrant to purchase Legacy Serina common stock was adjusted with such stock options and warrants henceforth representing the right to purchase a number of shares of Company common stock equal to 0.97682654 multiplied by the number of shares of Legacy Serina common stock previously represented by such options.
In March 2023, AgeX provided Legacy Serina with bridge financing in the form of a convertible promissory note for the principal amount of $10.0 million (the “AgeX-Serina Note”). See Note 6, Fair Value Measurements, for additional information on the AgeX-Serina Note.
As part of the recapitalization, the Company obtained the assets and liabilities listed below (in thousands):
Cash and cash equivalents$337 
Other current assets174 
Intangible assets576 
Accounts payable and accrued expenses(2,830)
Loan payable to Juvenescence(8,017)
Net liabilities acquired
(9,760)
Conversion of AgeX-Serina Note
10,721 
Total$961 

The Company recognized the assets and liabilities acquired and the conversion of the outstanding balance of the AgeX-Serina Note into shares of the Company’s common stock upon closing of the Merger, as a net increase in additional paid-in capital within equity for the year ended December 31, 2024.
v3.25.1
Selected Balance Sheet Components
 12 Months Ended
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Selected Balance Sheet Components Selected Balance Sheet Components
Prepaid expenses and other current assets
Prepaid expenses and other current assets were as follows (in thousands):
December 31,
 20242023
Prepaid technology access fee$1,333 $— 
Prepaid insurance192 — 
Other prepaid expenses402 — 
Other current assets77 — 
Total prepaid expenses and other current assets$2,004 $— 
Property and equipment, net
Property and equipment, net was as follows (in thousands):
December 31,
20242023
Computer equipment$— $30 
Equipment966 837 
Software136 96 
Total property and equipment, gross1,102 963 
Less: accumulated depreciation and amortization(601)(390)
Total property and equipment, net$501 $573 
Depreciation and amortization of property and equipment for each of the years ended December 31, 2024 and 2023 was $0.1 million.
Accrued liabilities
Accrued liabilities were comprised of the following (in thousands):
December 31,
20242023
Accrued severance$304 $— 
Accrued interest on convertible promissory notes— 558 
Accrued compensation559 13 
Other accrued expenses566 12 
Total accrued expenses$1,429 $583 
v3.25.1
Related Party Transactions
 12 Months Ended
Dec. 31, 2024
Related Party Transactions [Abstract]  
Related Party Transactions Related Party Transactions
Convertible notes agreement and asset contribution agreement
On March 26, 2024, AgeX entered into an Asset Contribution Agreement with UniverXome (the “Asset Contribution Agreement”) pursuant to which AgeX transferred to UniverXome all of AgeX’s capital stock in Reverse Bio and ReCyte, along with certain patents, patent applications, and other intellectual property, certain biological materials, certain trademarks and service marks, certain equipment, certain inventory, and certain files and records relating to the foregoing, and UniverXome assumed all of the Liabilities (as defined in the Asset Contribution Agreement) in existence as the Effective Time (as defined in the Merger Agreement) other than the Transaction Expenses (as defined in the Merger
Agreement) and certain other liabilities. Concurrently with the execution of the Asset Contribution Agreement, AgeX, and its subsidiaries UniverXome, Reverse Bio, and ReCyte (the “Subsidiary Obligors”), entered into an Agreement with Respect to the Convertible Notes (the “Convertible Notes Agreement”) with Juvenescence.
Pursuant to the Convertible Notes Agreement, AgeX transferred to UniverXome, and UniverXome assumed, all of AgeX’s rights and obligations under the 2022 Secured Note and 2023 Secured Note and related Security Agreements described below. Juvenescence agreed to release AgeX from its obligations under (i) the 2022 Secured Note and the 2023 Secured Note (collectively, the “Convertible Notes”), together with (ii) all agreements evidencing or securing the Convertible Notes, including the related Security Agreements, and UniverXome assumed all of AgeX’s obligations under the Convertible Notes and related agreements, including the Security Agreements. As a result, (i) Juvenescence agreed to look solely to UniverXome, and ReCyte and Reverse Bio as guarantors, for any and all obligations, including repayment, under the Convertible Notes, the Security Agreements, and related documents, and (ii) Juvenescence released its security interests in the assets of AgeX and certain subsidiaries, including its security interests in the stock of UniverXome, the stock and assets of Merger Sub, the stock and assets of NeuroAirmid, and certain cGMP embryonic cell lines used to support the NeuroAirmid business, and any security interest that it might have in the stock and assets of Merger Sub and Legacy Serina, while retaining its security interest in the stock and assets of ReCyte and Reverse Bio and in AgeX assets transferred to UniverXome. Juvenescence also agreed to provide the Company with a claims reserve for the purpose of settling and paying the costs associated with certain claims and demands against the Company, which claims reserve will be an additional debt obligation of UniverXome.
The Convertible Notes Agreement amended certain provisions of the 2022 Secured Note and 2023 Secured Note to eliminate (i) the provisions permitting Juvenescence and AgeX to convert outstanding amounts owed into shares of AgeX common stock, and (ii) certain related provisions.
The Convertible Notes Agreement includes a mechanism for adjusting the amount outstanding under the 2022 Secured Note as necessary for AgeX to have had $0.5 million of immediately spendable non-restricted cash net of all payables and other liabilities as of the closing of the Merger to meet the closing condition under the Merger Agreement.
Indebtedness exchange agreement and issuance of AgeX preferred stock
During July 2023, AgeX and Juvenescence entered into an Exchange Agreement pursuant to which AgeX issued shares of Series A Preferred Stock and Series B Preferred Stock to Juvenescence in exchange for the extinguishment of a total of $36.0 million of indebtedness under a Secured Convertible Facility Agreement (the “2020 Loan Agreement”), the 2022 Secured Note, and the 2023 Secured Note discussed below. The Series A Preferred Stock and Series B Preferred Stock automatically converted into shares of AgeX common stock on February 1, 2024.
2022 secured note
The following summary of the 2022 Secured Note is qualified by the terms of the Convertible Notes Agreement which substitutes UniverXome for AgeX as the “borrower” and primary obligor pursuant to the 2022 Secured Note and the Security Agreement described below, and which amends certain provisions of the 2022 Secured Note.
On February 14, 2022, AgeX and Juvenescence entered into a Secured Convertible Promissory Note (the “2022 Secured Note”) pursuant to which Juvenescence agreed to provide to AgeX a $13.2 million line of credit for a period of 12 months. The Company drew an initial $8.2 million of the line of credit and used $7.2 million to refinance the outstanding principal and the loan origination fees under a prior loan agreement with Juvenescence. On February 9, 2023, AgeX and Juvenescence entered into an Amended and Restated Secured Convertible Promissory Note which amended and restated the 2022 Secured Note and added $2.0 million to the line of credit available to be borrowed by AgeX, under the 2022 Secured Note subject to Juvenescence’s discretion to approve each loan draw. On May 9, 2023, AgeX and Juvenescence entered into an Allonge and Second Amendment to Amended and Restated Convertible Promissory Note (the “Second Amendment”) that increased the amount of the line of credit available to AgeX by $4.0 million, subject to the terms of the 2022 Secured Note and Juvenescence’s discretion to approve and fund each of AgeX’s future draws of that additional amount of credit. On June 2, 2023, AgeX and Juvenescence entered into a Third Amendment to Amended and Restated Convertible Promissory Note (the “Third Amendment’), which provided that (i) AgeX could draw on the available portion of the line of credit under the 2022 Secured Note until the earlier of the date a Qualified Offering as defined in the 2022 Secured Note is consummated by AgeX or October 31, 2023 (subject to Juvenescence’s discretion to approve each loan draw as provided in the 2022 Secured Note), (ii) AgeX would not be obligated to issue additional common stock purchase warrants to Juvenescence in connection with the receipt of loan funds made available pursuant to the Second Amendment,
and (iii) the definition of “Reverse Financing Condition” was amended to extend to June 20, 2023 the referenced deadline for fulfillment of the condition to permit borrowing or other incurrence of indebtedness by Reverse Bio.
On July 31, 2023, AgeX and Juvenescence entered into a Fourth Amendment (the “Fourth Amendment”) to the 2022 Secured Note, which provided that (i) the definition of Reverse Financing Condition was amended to extend to October 31, 2023 the referenced deadline for fulfillment of the condition to permit borrowing or other incurrence of indebtedness by Reverse Bio, and (ii) certain aspects of the loan conversion provisions of the 2022 Secured Note were amended. On November 9, 2023, AgeX and Juvenescence entered into the Allonge and Fifth Amendment to Amended and Restated Convertible Promissory Note (the “Fifth Amendment”) that increased the amount of the line of credit available to AgeX by $4.4 million, subject to the terms of the 2022 Secured Note and Juvenescence’s discretion to approve and fund each of AgeX’s future draws of that additional amount of credit. Concurrently with the execution of the Fifth Amendment, AgeX also entered into an additional Pledge Agreement to add shares of a subsidiary to the collateral under the Security Agreement, and AgeX’s subsidiaries ReCyte, Reverse Bio, and UniverXome each entered into a Guaranty Agreement and Joinder Agreement pursuant to which each of them agreed to guaranty AgeX’s obligations to Juvenescence pursuant to the 2022 Secured Note, as amended by the Fifth Amendment, and to grant Juvenescence a security interest in their respective assets pursuant to the Security Agreement to secure their obligations to Juvenescence.
On February 9, 2024, AgeX and Juvenescence executed a Sixth Amendment to Amended and Restated Convertible Promissory Note (the “Sixth Amendment”) that extended to May 9, 2024 the “Repayment Date” on which the outstanding principal balance and accrued loan origination fees will become due and payable pursuant to the 2022 Secured Note.
On March 26, 2024, AgeX entered into an Allonge and Seventh Amendment to the Amended and Restated Convertible Promissory Note (the “Seventh Amendment”) that provided the Company an additional $2.4 million of credit subject to the terms of the 2022 Secured Note which was drawn entirely on March 29, 2024.
On May 8, 2024, the Company entered into an Allonge and Eighth Amendment to the Amended and Restated Convertible Promissory Note that extended to December 31, 2024 the “Repayment Date” on which the outstanding principal balance and accrued loan origination fees will become due and payable pursuant to the 2022 Secured Note and provided the Company an additional $0.5 million of credit subject to the terms of the 2022 Secured Note which was drawn entirely on May 9, 2024. The funds were used to pay certain litigation settlement expenses and related litigation costs.
On October 15, 2024, the Company entered into an Allonge and Ninth Amendment to the Amended and Restated Convertible Promissory Note that provided an increase in the Incremental Commitment amount of $0.1 million. The funds were used to pay certain litigation settlement expenses and related litigation costs.
As of December 31, 2023, the Company had borrowed a total of $20.2 million under the 2022 Secured Note, of which $7.5 million was borrowed during 2023. In July 2023, $18.0 million of 2022 Secured Note indebtedness, comprised of $16.7 million borrowing and $1.3 million of accrued loan origination fees, was extinguished in exchange for shares of AgeX Series A Preferred Stock and Series B Preferred Stock pursuant to the Exchange Agreement between AgeX and Juvenescence. During the year ended December 31, 2024, the Company borrowed $6.4 million under the 2022 Secured Note.
As an arrangement fee for the 2022 Secured Note, AgeX agreed to pay Juvenescence an origination fee in an amount equal to 4% of the amount of each draw of loan funds, which will accrue as each draw is funded, and an additional 4% of all the total amount of funds drawn that will accrue following the end of the period during which funds may be drawn from the line of credit. The origination fee will become due and payable on the repayment date or in a pro rata amount with any prepayment in whole or in part of the outstanding principal balance of the 2022 Secured Note.
2022 Warrants – Upon each drawdown of funds under the 2022 Secured Note prior to June 2, 2023 when the Third Amendment went into effect, AgeX issued to Juvenescence warrants to purchase shares of AgeX common stock (“2022 Warrants”). The 2022 Warrants are governed by the terms of a Warrant Agreement between AgeX and Juvenescence. The number of 2022 Warrants issued with respect to each draw of loan funds was equal to 50% of the number determined by dividing the amount of the applicable loan draw by the applicable Market Price. The Market Price was the last closing price per share of AgeX common stock on the NYSE American preceding the delivery of the notice from AgeX requesting the draw of funds that triggered the obligation to issue 2022 Warrants.
As of December 31, 2023, AgeX had issued to Juvenescence 2022 Warrants to purchase a total of 294,482 shares of AgeX common stock, of which 2022 Warrants to purchase 53,980 shares of AgeX common stock were issued during the year
ended December 31, 2023. The exercise prices of the 2022 Warrants issued through December 31, 2023 ranged from $20.75 per share to $30.94 per share representing the market closing price of AgeX common stock on the NYSE American on the one day prior to delivery of the drawdown notices. However, 2022 Warrants to purchase a total of 164,889 shares of AgeX common stock were cancelled pursuant to the Merger Agreement and the remaining 2022 Warrants to purchase a total of 129,593 shares of common stock at prices ranging from $20.75 to $25.01 remain in effect. The number of shares issuable upon exercise of the 2022 Warrants and the exercise price per share are subject to adjustment upon the occurrence of certain events such as a stock split or reverse split or combination of the common stock, stock dividend, recapitalization or reclassification of the common stock, and similar events, and have been adjusted to give effect to the a 1 for 35.17 reverse stock split that AgeX implemented on March 14, 2024. See Note 7, Stockholders’ Equity/(Deficit). The expiration dates of the 2022 Warrants range from June 5, 2025 to April 3, 2026.
Conversion of loan amounts to common stock – The 2022 Secured Note included provisions allowing AgeX or Juvenescence to convert the loan balance and any accrued but unpaid origination fee into AgeX common stock; however, those provisions were eliminated from the 2022 Secured Note pursuant to the Convertible Notes Agreement.
Default provisions – The loan agreement also includes customary events of default, including but not limited to the nonpayment of principal or interest, violations of covenants, material adverse changes, attachment, levy, restraint on business, cross-defaults on material indebtedness, bankruptcy, delisting, material judgments, misrepresentations, governmental approvals, and disposal of material assets. Upon an event of default, the outstanding loan balance and origination fees may become immediately due and payable prior to the mandatory repayment date.
2023 Secured note
The following summary of the 2023 Secured Note is qualified by the terms of the Convertible Notes Agreement which substitutes UniverXome for AgeX as the “borrower” and primary obligor pursuant to the 2023 Secured Note and the Security Agreement described below, and which amends certain provisions of the 2023 Secured Note.
On March 13, 2023, AgeX and Juvenescence entered into a $10.0 million Secured Convertible Promissory Note (the “2023 Secured Note”) pursuant to which Juvenescence loaned to AgeX $10.0 million. AgeX used the loan proceeds to finance a $10.0 million loan to Legacy Serina which was converted into Legacy Serina common stock in connection with the Merger.
On July 31, 2023, AgeX and Juvenescence entered into an amendment to the 2023 Secured Note that mirrors the amendments of the 2022 Secured Note pursuant to the Fourth Amendment of the 2022 Secured Note described above and also modified certain aspects of the conversion provisions of the 2023 Secured Note. The outstanding principal balance of the 2023 Secured Note was scheduled to become due and payable on March 13, 2026. In lieu of accrued interest, AgeX agreed to pay Juvenescence an origination fee in an amount equal to 7% of the loan funds disbursed to AgeX, which will accrue in two installments. The origination fee will become due and payable on the earliest to occur of (i) repayment of the 2023 Secured Note in whole or in part (provided that the origination fee shall be prorated for the amount of any partial repayment) and (ii) the acceleration of the maturity date of the 2023 Secured Note following an Event of Default as defined in the 2023 Secured Note.
During July 2023, the 2023 Secured Note indebtedness, plus a portion of the accrued loan origination fees, was exchanged for shares of AgeX Series B Preferred Stock pursuant to the Exchange Agreement.
The 2023 Secured Note included provisions allowing AgeX or Juvenescence to convert the loan balance and any accrued but unpaid origination fee into the Company common stock; however, those provisions were eliminated from the 2023 Note pursuant to the Convertible Notes Agreement.
The 2023 Secured Note includes certain covenants that among other matters require financial reporting and impose certain restrictions on UniverXome that are substantially the same as those under the 2022 Secured Note.
Security agreement
AgeX entered into a Security Agreement on February 14, 2022 in favor of Juvenescence as the secured party in connection with the 2022 Secured Note, and subsequently an Amended and Restated Security Agreement that amended the February 14, 2022 Security Agreement and added the 2023 Secured Note to the obligations secured by the Security Agreement. The Security Agreement, as so amended, granted Juvenescence a security interest in substantially all of the assets of AgeX,
including a security interest in shares of AgeX subsidiaries that hold certain assets, as collateral for AgeX’s loan obligations. Pursuant to the Convertible Notes Agreement, UniverXome assumed AgeX’s obligations under the Security Agreement and Juvenescence released its security interests in the assets of AgeX and certain subsidiaries, including its security interests in the stock of UniverXome, the stock and assets of Merger Sub, the stock and assets of NeuroAirmid, and certain cGMP embryonic cell lines used to support the NeuroAirmid business, and any security interest that it might have in the stock and assets of Merger Sub and Legacy Serina, while retaining its security interest in the stock and assets of ReCyte and Reverse Bio and in AgeX assets transferred to UniverXome. If an Event of Default occurs under the 2022 Note, the 2023 Note or the Security Agreement, Juvenescence will have the right to foreclose on the assets pledged as collateral.
Indemnification agreements
On March 13, 2023, AgeX executed that certain Letter of Indemnification in Lieu of or Supplemental to a Medallion Signature Guarantee (“Letter of Indemnification”), pursuant to which AgeX agreed to indemnify American Stock Transfer & Trust Company, LLC and its affiliates, successors and assigns (the “AST Indemnity”) from and against any and all claims, damages, liabilities or losses arising out of the transfer of all of the AgeX common stock held by Juvenescence to its wholly-owned subsidiary, Juvenescence US Corp. (the “Share Transfer”). In connection with AgeX’s execution of the Letter of Indemnification, AgeX and Juvenescence entered into that certain Transfer of Shares of AgeX Therapeutics, Inc. Common Stock – Indemnification Agreement, pursuant to which Juvenescence agreed to indemnify AgeX against any and all claims, damages, liabilities or losses arising out of the Share Transfer or AST Indemnity.
On December 21, 2023, AgeX executed that certain Letter of Indemnification in Lieu of or Supplemental to a Medallion Signature Guarantee (the “ETC Letter of Indemnification”), pursuant to which AgeX agreed to indemnify Equiniti Trust Company LLC and its affiliates, successors and assigns (the “ETC Indemnity”) from and against any and all claims, damages, liabilities or losses arising out of the transfer 467,657 shares of AgeX common stock held by Juvenescence US Corp. to JuvVentures (the “JUV US Share Transfer”). In connection with AgeX’s execution of the ETC Letter of Indemnification, AgeX, Juvenescence, the ultimate parent company of Juvenescence US Corp. and JuvVentures, entered into that certain Transfer of Shares of AgeX Therapeutics, Inc. Common Stock – Indemnification Agreement, pursuant to which Juvenescence agreed to indemnify AgeX against any and all claims, damages, liabilities or losses arising out of the JUV US Share Transfer or ETC Indemnity.

Sale of subsidiary to Juvenescence
On December 23, 2024, the Company entered into the Stock Purchase Agreement with Juvenescence, pursuant to which Juvenescence purchased all of the outstanding shares of UniverXome, thereby assuming all Legacy Assets AgeX transferred to UniverXome prior to the Merger. The Legacy Assets included all of AgeX’s interests in ReCyte, Reverse Bio along with certain patents, patent applications, and other intellectual property, certain biological materials, certain trademarks and service marks, certain equipment, certain inventory, and certain files and records relating to the foregoing. As consideration for the purchase of UniverXome, Juvenescence assumed the net assets of UniverXome primarily consisting of intangible assets, net, of $0.5 million, and approximately $11.3 million of secured debt, consisting of the 2022 Secured Note and 2023 Secured Note owed by UniverXome to Juvenescence in addition to a nominal cash payment. The debt assumed by Juvenescence was secured by substantially all of the assets of UniverXome. As a result of the sale, the Company derecognized all assets and liabilities of UniverXome with a corresponding increase to additional paid-in capital from Juvenescence calculated as the difference between the carrying amount of the extinguished debt and the fair value of the reacquisition price of the debt. For the year ended December 31, 2024, the Company recognized a $10.9 million capital contribution on the consolidated statement of redeemable convertible preferred stock and stockholders' equity/(deficit).
v3.25.1
Fair Value Measurements
 12 Months Ended
Dec. 31, 2024
Fair Value Disclosures [Abstract]  
Fair Value Measurements Fair Value Measurements
The Company had the following liabilities measured at fair value on a recurring basis (in thousands):
Balance at December 31, 2024Level 1Level 2Level 3
Liabilities:    
Warrant liability$3,582 $— $— $3,582 
Total$3,582 $— $— $3,582 
Balance at December 31, 2023Level 1Level 2Level 3
Liabilities:
Convertible promissory notes$2,983 $— $— $2,983 
Total$2,983 $— $— $2,983 
Convertible Promissory Notes
AgeX-Serina Note
On March 15, 2023, Legacy Serina issued the AgeX-Serina Note in the amount of $10.0 million to AgeX. The AgeX-Serina Note bore interest at 7% per annum and was scheduled to mature on March 15, 2026. Serina borrowed the $10.0 million pursuant to the AgeX-Serina Note to provide for general working capital needs.
Serina elected to initially and subsequently measure the AgeX-Serina Note in its entirety at fair value, with changes in fair value recognized in earnings. The fair value inception date adjustment on the instrument is recorded as a component of other income in Serina’s consolidated statements of operations.
On March 15, 2023, the fair value of the $10.0 million principal amount under the AgeX-Serina Note was evaluated and an adjustment to reduce the fair value of the principal balance to $7.8 million was recorded at that time. On the date of the Merger, the AgeX-Serina Note was remeasured to its fair value of $10.7 million as it converted into equity upon the Merger. See Note 3, Recapitalization for details. The change in fair value recognized during the years ended December 31, 2024 and 2023 amounted to approximately $7.0 million loss and $7.0 million gain, respectively.
Legacy Serina Convertible Notes
From September 2022 through February 2023, Legacy Serina issued interest-bearing Convertible Promissory Notes (the “Legacy Serina Convertible Notes”) to various investors in the principal amount of $1.5 million. The Legacy Serina Convertible Notes bore interest at 6% per annum and were scheduled to become due and payable by Legacy Serina two years from the respective issuance dates. The Legacy Serina Convertible Notes provided that upon a Qualified Equity Financing event in which Serina sells shares of Preferred Stock for aggregate proceeds of at least $15.0 million, the principal and outstanding interest on the Legacy Serina Convertible Notes would automatically convert into shares of Legacy Serina’s Preferred Stock issued in the Qualified Financing at a conversion price of the lesser of (i) a 20% discount to the price paid by purchasers in the Qualified Financing and (ii) the quotient resulted from dividing $100 million by the fully diluted capitalization of Legacy Serina immediately prior to the Qualified Financing. If Serina were to enter into a Non-Qualified Equity Financing (less than $15 million in proceeds), the holders of the Legacy Serina Convertible notes would have had the option to convert the Legacy Serina Convertible Notes into shares of Serina’s Preferred Stock issued in the Non-Qualified Financing at the price paid per share. Serina had the right to optionally convert the Legacy Serina Convertible Notes into Legacy Serina Series A-5 Preferred Stock at a price of $13.31 per share, and a warrant to purchase shares of Legacy Serina Series A-5 Preferred Stock with an exercise price of $20.47, and an expiration date of December 31, 2024. If a Change in Control or an IPO were to occur prior to a Qualified Financing, then the holders of Legacy Serina Convertible Notes would have had the option to convert outstanding principal and interest into common stock at a price per share equal to an amount obtained by dividing (i) the Post-Money Valuation Cap ($100 million) by (ii) the Fully Diluted Capitalization, as such terms were defined in the Legacy Serina Convertible Notes, immediately prior to the conversion.
Upon a change in control, the Legacy Serina Convertible Note holders were entitled to require Legacy Serina to repay the outstanding principal and accrued but unpaid interest in cash.
Serina elected to initially and subsequently measure the Legacy Serina Convertible Notes in their entirety at fair value, with changes in fair value recognized in earnings. The fair value inception date adjustment on the instrument is recorded as a component of other income in Serina’s consolidated statements of operations. The change in fair value of the instrument since inception date is recorded on a separate line item as a component of other income in Serina’s consolidated statements of operations.
On July 26, 2023, all of the Legacy Serina Convertible Notes were converted into 115,171 shares of Legacy Serina Series A-5 Preferred Stock. As provided for in the note agreements, the holders of the Legacy Serina Convertible Notes also received warrants to purchase an additional 115,171 shares of Legacy Serina Series A-5 Preferred Stock. See Note 7, Stockholders’ Equity/(Deficit) for discussion of Legacy Serina warrants assumed by the Company upon consummation of the Merger on March 26, 2024. The change in fair value of the Legacy Serina Convertible Notes for the year ended December 31, 2023 was a loss of $0.6 million.

The following is a reconciliation of the beginning and ending balances for the AgeX-Serina Note and the Legacy Serina Convertible Notes liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the years ended December 31, 2024 and 2023, respectively (in thousands):
 AgeX-Serina
Note 		 Legacy Serina
Convertible Notes
Balance as of December 31, 2023$2,983 $— 
Conversion into equity(10,000)— 
Change in fair value7,017 — 
Balance as of December 31, 2024$— $— 
 AgeX-Serina
Note 		Legacy Serina
Convertible Notes
Balance as of December 31, 2022$— $1,617 
Convertible debt issuance10,000 100 
Inception adjustment(2,240)— 
Notes converted to Series A-5 pref. stock— (963)
Notes converted to warrants— (175)
Change in fair value(4,777)(579)
Balance as of December 31, 2023$2,983 $— 
Warrant Liability
The Company classifies the Post-Merger Warrants, Incentive Warrants and Replacement Incentive Warrants (collectively, the “Merger Warrants”) as liabilities. At the end of each reporting period, changes in fair value during the period are recognized as a component of other income (expense), net within the consolidated statements of operations. The change in fair value of these warrant liabilities recognized during the year ended December 31, 2024, amounted to a 13.2 million gain. The Company will continue adjusting the warrant liability for changes in fair value until the earlier of a) the exercise or expiration of the warrants or b) the redemption of the warrants, at which time the warrants will be reclassified to additional paid-in capital.
Upon consummation of the Merger, the Company assumed the outstanding, unexercised warrants to purchase Legacy Serina capital stock ("Assumed Warrants") as liabilities. All Assumed Warrants were adjusted such that after the Merger each such Assumed Warrant represents the right to purchase a number of shares of Company common stock equal to 0.97682654 multiplied by the number of shares of Legacy Serina common stock issuable upon the exercise of such Assumed Warrant prior to the Merger. The Assumed Warrants have an exercise price of $20.47 per share and expired on December 31, 2024. As such, they are no longer outstanding as of December 31, 2024.
The following is a reconciliation of the beginning and ending balances of warrant liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the year ended December 31, 2024 (in thousands):

Merger Warrants
Balance as of December 31, 2023$— 
Fair value at inception of Post-Merger Warrants 18,501 
Exercise(1,372)
Derecognition of Incentive Warrants(1,798)
Initial recognition of fair value of Replacement Incentive Warrants
1,407 
Change in fair value(13,156)
Balance at December 31, 2024$3,582 
There were no warrant liabilities for the year ended December 31, 2023.
The Company estimates the fair value of warrants using the Black-Scholes-Merton option pricing model with the following assumptions during the year ended December 31, 2024:

Merger Warrants
Expected volatility
99.15% -125.89%
Expected term (in years)
0.6 – 3.24
Risk-free interest rate
4.14% - 4.28%
Expected dividend yield0.00 %
Expected volatility for the periods post Merger consummation on March 26, 2024 is based on historical volatility of the Company, while pre Merger periods use the historical volatility of comparable public entities as an estimate. The Company estimates the expected term using time to expiration of the warrant. The risk-free interest rate is the yield on a U.S. Treasury zero-coupon issue with a remaining term equal to or approximating the expected term of the warrant.
See Note 7, Stockholders’ Equity/(Deficit) for further details regarding the Warrants.
v3.25.1
Stockholders’ Equity/(Deficit)
 12 Months Ended
Dec. 31, 2024
Equity [Abstract]  
Stockholders’ Equity/(Deficit) Stockholders’ Equity/(Deficit)
Redeemable Convertible Preferred Stock
All Legacy Serena redeemable convertible preferred stock was converted into common stock at the time of the Merger as described in Note 1.
The table below presents Legacy Serina redeemable convertible preferred stock information adjusted for the 0.97682654 Exchange Ratio as of December 31, 2023 (in thousands other than per share price).
Preference OrderDesignationShares
Designated		Shares
Issued and
Outstanding		Issue Price
per Share		Carrying ValueLiquidation Preference
#1Series A Preferred Stock391391$5.12 $2,000 $2,002 
#2Series A-1 Preferred Stock2932936.82 1,998 1,998 
#3Series A-2 Preferred Stock1,0911,09110.17 11,085 11,095 
#4Series A-3 Preferred Stock48748712.80 6,240 6,234 
#5Series A-4 Preferred Stock70270213.31 9,347 9,344 
#6Series A-5 Preferred Stock1,95447413.31 5,734 6,309 
  4,9183,438 $36,404 $36,982 
Common Stock
The holders of common stock are entitled to one vote for each share of common stock which is outstanding on all matters on which stockholders are entitled to vote generally. The holders of shares of common stock do not have cumulative voting rights. Except as otherwise required by law, holders of common stock are not be entitled to vote on any amendment to our Amended and Restated Certificate of Incorporation that relates solely to the terms, number of shares, powers, designations, preferences or relative, participating, optional or other special rights, or to qualifications, limitations or restrictions thereof, of one or more outstanding series of preferred stock if the holders of such affected series are entitled to vote thereon pursuant to our Amended and Restated Certificate of Incorporation or pursuant to the Delaware General Corporation Law. Holders of shares of our common stock will not have any dividend, liquidation, preemptive, subscription or conversion rights, and there will not be any redemption or sinking fund provisions applicable to our common stock.
In March 2024, the Company amended and restated its certificate of incorporation to increase the authorized shares of common stock to consist of 40,000,000 shares of common stock, par value $0.0001 per share, and 5,000,000 shares of preferred stock, par value $0.0001 per share.
As of December 31, 2024 and 2023, the Company had reserved common stock on an as-converted basis for future issuance as follows (in thousands):
December 31,
20242023
Outstanding common stock warrants
1,997359
Outstanding common stock options under the Plans
3,2211,716
Reserved for future stock option grants
1,97713
Total common stock reserved for future issuance
7,1952,088
Warrants
Merger Warrants
On March 19, 2024, the Company issued to each holder of AgeX common stock as of the dividend record date, March 18, 2024, three warrants (“Post-Merger Warrants”) for each five shares of AgeX common stock held by such stockholder. Each Post-Merger Warrant is exercisable for one “Unit” at a price equal to $13.20 per Unit and will expire on July 31, 2025. Each Unit will consist of (i) one share of Company common stock and (ii) one warrant (“Incentive Warrant”). Each Incentive Warrant is exercisable for one share of Company common stock at a price equal to $18.00 per warrant and will expire on the four-year anniversary of the closing date of the Merger. As of December 31, 2024 there were 366,691 Post-Merger Warrants issued and outstanding. The Company classifies the Post-Merger Warrants and the Incentive Warrants as liabilities. See Note 6, Fair Value Measurements, regarding accounting for warrant liabilities.
The Side Letter provided, among other things, that Juvenescence will exercise all Post-Merger Warrants it holds to provide the Company an additional $15.0 million in capital according to the following schedule: (x) at least one-third on or before May 31, 2024, (y) at least one-third on or before November 30, 2024, and (z) at least one-third on or before June 30, 2025. Juvenescence received 1,133,594 Post-Merger Warrants. On June 6, 2024, Juvenescence exercised Post-Merger Warrants to purchase 377,865 shares of the Company’s common stock at an exercise price of $13.20 per share, for a total purchase price of $5.0 million. In addition to the shares of common stock, upon exercise of the Post-Merger Warrants, Juvenescence also received Incentive Warrants to purchase 377,865 shares of common stock with an exercise price of $18.00 per share that expire on March 26, 2028.
Replacement Incentive Warrants
On November 26, 2024, the Company entered into the agreement with Juvenescence (the "Agreement") whereby the Company will issue 1,000,000 shares of common stock at $10.00 per share, for an aggregate amount of $10 million in two equal tranches and to surrender to the Company its outstanding Post-Merger Warrants for the purchase of 755,728 shares of common stock, including all underlying Incentive Warrants issuable upon exercise thereof. In connection with Agreement, the Company issued to Juvenescence warrants to purchase 755,728 shares of common stock at an exercise price of $18.00 per share (the “Replacement Incentive Warrants”). The Replacement Incentive Warrants expire on March 26, 2028. As a result of the transaction, the Company derecognized warrant liabilities of $1.8 million associated with the surrendered and cancelled Post-Merger and Incentive Warrants and recorded the initial warrant liabilities of $1.4 million associated with the Replacement Incentive Warrants in the consolidated balance sheet as of December 31, 2024.
The closing on the first tranche occurred on November 27, 2024 and the Company issued 500,000 shares of its common stock to Juvenescence for $5.0 million. Juvenescence also agreed to purchase the second tranche of 500,000 shares of common stock and receive corresponding Replacement Incentive Warrants for a second aggregate payment of $5.0 million in January 2025. In connection with the first tranche closing, Juvenescence pledged 122,136 shares of common stock to the Company as security for the closing of the second tranche. The second tranche closed on January 31, 2025.
As of December 31, 2024, Juvenescence held one Post-Merger Warrants, 377,865 Incentive Warrants and 755,728 Replacement Incentive Warrants. The Company classifies the Replacement Incentive Warrants as liabilities. See Note 6, Fair Value Measurements, regarding accounting for warrant liabilities.
Details of the Merger Warrants activity for the year ended December 31, 2024 are as follows ( in thousands):
Post-Merger Warrants Incentive WarrantsReplacement Incentive Warrants
Balance at December 31, 2023— — — 
Warrants issued1,500 378 — 
Warrants exercised(378)— — 
Warrants exchanged(755)— 756 
Balance at December 31, 2024367 378 756 
Assumed Warrants
Upon consummation of the Merger, the Company's Assumed Warrants were adjusted such that after the Merger each such Assumed Warrant represents the right to purchase a number of shares of Company common stock equal to 0.97682654 multiplied by the number of shares of Legacy Serina common stock issuable upon the exercise of such Assumed Warrant prior to the Merger. All 473,681 Assumed Warrants had an exercise price of $20.47 per share and expired on December 31, 2024, none were outstanding as of December 31, 2024.
Former AgeX Warrants
As of December 31, 2024, there are 129,593 warrants issued and outstanding with exercise prices ranging from $20.75 to $25.01 and expiration dates ranging from June 5, 2025 to April 3, 2026. These warrants were issued in connection with drawdowns of loan funds by AgeX from Juvenescence under the 2022 Secured Note and were equity classified. On March 26, 2024, as per the terms of the Side Letter executed concurrently with the Merger Agreement on August 29, 2023, all “out of the money” AgeX warrants were canceled. The number of shares of common stock issuable upon exercise of the
remaining “in the money warrants” and the exercise prices of those warrants were adjusted for the reverse stock split ratio of 1 for 35.17.
v3.25.1
Stock-Based Awards
 12 Months Ended
Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]  
Stock-Based Awards Stock-Based Awards
Equity Incentive Plan Awards
Serina 2024 Inducement Equity Plan
On August 15, 2024, the Company’s Board of Directors adopted the 2024 Inducement Equity Plan, (the “2024 Inducement Plan”). Under the 2024 Inducement Plan, the Company has reserved 1,000,000 stock options to be granted to new employees or non-employee directors. The Company may also grant restricted stock for the settlement of restricted stock units which are hypothetical units issued with reference to common stock (“RSUs”) or stock appreciation rights (“SARs”) under the Inducement Plan. The Plan also permits the Company to issue such other securities as its Board of Directors or the Compensation Committee administering the Inducement Plan may determine. Options under this plan primarily have a ten-year life, vest and therefore become exercisable in periodic installments as determined by the Board or Committee or based upon the attainment of a Performance Goal or the occurrence of a specified event. The vesting provisions of individual options may vary. As of December 31, 2024, options to purchase 45,000 shares of the Company's common stock were outstanding under the 2024 Inducement Equity Plan, which options have an exercise price of $5.30 per share and expire in November 2034. As of December 31, 2024, zero stock options had been exercised and there were 955,000 shares available for grant under the 2024 Inducement Plan.
Serina 2024 Equity Incentive Plan
On March 27, 2024, the Company’s Board of Directors adopted the 2024 Equity Incentive Plan, (the “2024 Incentive Plan”) which provided 1,725,000 stock option to be granted to employees, directors, and consultants. The Company may also grant RSUs or SARs under the 2024 Incentive Plan. On December 13, 2024, stockholders approved 950,000 additional shares of the Company’s common stock to be added to the 2024 Incentive Plan for future issuance. The 2024 Incentive Plan also permits the Company to issue such other securities as its Board of Directors or the Compensation Committee administering the Incentive Plan may determine. Options under this plan primarily have a ten-year life, vest and therefore become exercisable in periodic installments as determined by the Board of Directors or Compensation Committee or based upon the attainment of a performance goal or the occurrence of a specified event. The vesting provisions of individual options may vary. As of December 31, 2024, options to purchase 1,652,792 shares of the Company's common stock were outstanding under the 2024 Incentive Plan, which options have exercise prices ranging from $6.66 to $14.87 per share and expire on dates ranging from March 2034 to September 2034. As of December 31, 2024, zero stock options had been exercised and there were 1,022,208 shares available for grant under the 2024 Incentive Plan.
Serina 2017 Stock Option Plan
In 2017, the Legacy Serina’s Board of Directors adopted the Serina Therapeutics, Inc. 2017 Stock Option Plan (the “2017 Option Plan”) that provides for the granting of stock options to employees. Pursuant to the Merger Agreement, the Company assumed the outstanding stock options granted by Legacy Serina under the 2017 Option Plan. The options were adjusted such that after the Merger each such option granted and outstanding under the 2017 Option Plan represents the right to purchase a number of shares of Company common stock equal to 0.97682654 multiplied by the number of shares of Legacy Serina common stock issuable upon the exercise of such options granted and outstanding under the 2017 Option Plan prior to the Merger. As of December 31, 2024, options to purchase 1,521,172 shares of the Company's common stock were outstanding under the 2017 Option Plan, which options have an exercise price of $0.06 per share and expire on dates ranging from July 2027 to December 2032. For the year ended December 31, 2024, 194,932 stock options under the 2017 Option Plan had been exercised. Pursuant to the Merger Agreement, no further options shall be granted under the 2017 Option Plan.
Serina 2017 Equity Incentive Plan
Under the Serina 2017 Equity Incentive Plan, as amended (the “2017 Incentive Plan” formerly AgeX 2017 Equity Incentive Plan), the Company has reserved 241,683 shares of common stock for the grant of stock options or the sale of Restricted Stock or for the settlement of RSUs. Pursuant to the Merger Agreement, all “out of the money” options (meaning those options with an exercise price equal to or greater than $0.7751 on a pre-reverse stock split basis) were canceled and no further options shall be granted under the 2017 Incentive Plan. The “in the money” stock options were adjusted for the reverse stock split ratio of 1 for 35.17. As of December 31, 2024, there were 1,812 stock options granted
and outstanding under the 2017 Equity Incentive Plan, which options have an exercise of $13.19 per share and expiration dates in January 2034. As of December 31, 2024, no stock options under the 2017 Incentive Plan had been exercised.
A summary of Serina stock option activity under all plans and related information are as follows (in thousands, except weighted average exercise price):
Number
of Options
Outstanding		Weighted-
Average
Exercise Price
(per share)		Weighted-Average Remaining Contractual Term
(in years)		Aggregate Intrinsic Value
(in thousands)
Balance at December 31, 20231,716$0.067.5$— 
Assumed options in connection with the Merger12$24.04
Granted1,713$9.03
Exercised(195)$0.06$1,753 
Cancelled/Forfeited(25)$13.59
Balance at December 31, 20243,221$4.817.7$7,530 
Options exercisable December 31, 20241,677$1.056.0$7,530 
Stock-based Compensation Expense
During the year ended December 31, 2024, Company granted stock options to purchase 1,713,000 shares of common stock to certain employees and consultants, with a weighted average grant date fair value of $7.83 per share. There were no stock options granted during the year ended December 31, 2023. The aggregate intrinsic value of options exercised during the years ended December 31, 2024 and 2023 was $1.8 million and $0.2 million, respectively. Total unrecognized compensation cost related to unvested stock option grants of $10.8 million as of December 31, 2024 is expected to be recognized over weighted average period of 3.1 years.
Stock-based compensation expense has been allocated to operating expenses as follows (in thousands):
Year ended December 31,
20242023
Research and development$551 $— 
General and administrative2,044 25 
Total stock-based compensation expense$2,595 $25 
The fair value of each option award is estimated on the date of grant using a Black-Scholes option pricing model applying the weighted-average assumptions including the market price of the underlying common stock, expected option life, risk-free interest rates, volatility, and dividend yield. The assumptions that were used to calculate the grant date fair value of employee and non-employee stock option grants for the years ended December 31, 2024 and 2023 were as follows:
Year ended December 31,
2024(1)
2023(2)
Expected life (in years)
5.0 - 6.1
— 
Volatility
112.67% - 118.33%
— 
Risk-free interest rates
3.54% - 4.65%
— 
Dividend yield—— 
(1)Relates to stock options granted under the Serina 2024 Equity Incentive Plan and the Serina 2024 Inducement Equity Plan during the period.
(2)There were no stock options granted during the year.
Each of these inputs is subjective and generally requires significant judgment.
Expected Life — The expected life represents the weighted-average period that the Company's stock-based awards are expected to remain outstanding and is determined using the "simplified method", whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the option.
Volatility — The volatility is estimated using the historical volatilities of comparable publicly traded companies over a period equal to the expected life as the Company does not have sufficient trading history for its common stock price.
Risk-free interest rates — The risk-free interest rate is determined by reference to the U.S. Treasury fixed rate maturities issues similar in duration to the expected life of the award.
Dividend yield — The Company currently has never paid and has no plans to pay any dividends on its common stock. Therefore, the Company has used an expected dividend rate of zero.
The Company does not recognize deferred income taxes for incentive stock option compensation expense and records a tax deduction only when a disqualified disposition has occurred.
v3.25.1
Profit Sharing Plan
 12 Months Ended
Dec. 31, 2024
Postemployment Benefits [Abstract]  
Profit Sharing Plan Profit Sharing Plan
Through its wholly owned subsidiary, Legacy Serina, the Company has established a 401(k) profit sharing plan (the “PSP”) for all eligible employees. The PSP provides for eligible employee contributions subject to certain annual Internal Revenue Code limits. For participants who are age 50 or older during any calendar year, additional employee contributions are allowed under the PSP, subject to Internal Revenue Code limits.
Employer contributions, if any, may include matching contributions and profit sharing contributions, both of which are made on a discretionary basis and are subject to service and employment requirements. Employer matching contributions and employer profit sharing contributions vest based on a graded vesting schedule. The Company made no discretionary employer matching or employer profit sharing contributions for the years ended December 31, 2024 or 2023.
v3.25.1
License Revenue
 12 Months Ended
Dec. 31, 2024
Other Industries [Abstract]  
License Revenue License Revenue
In October 2023, the Company entered into a non-exclusive license agreement with Pfizer, Inc. (“Pfizer”) for the use of its POZ polymer technology in lipid nanoparticle drug delivery formulations. The agreement grants Pfizer non-exclusive rights to certain intellectual property, know-how, and proprietary technologies. Under the terms of the agreement, Pfizer is authorized to develop, manufacture, market, and commercialize products incorporating the licensed technology with respect to a specific POZ polymer structure in one field. The agreement outlines the protection and enforcement of intellectual property rights related to the licensed technology. Pfizer is obligated to use commercially reasonable diligent efforts to develop and commercialize licensed products, and to use such efforts to accomplish specified development and commercial objectives. The agreement includes a one-time upfront payment of $3 million that was received on December 15, 2023, milestone payments due upon the achievement of specific development, regulatory, and commercial milestones, and a royalty on net sales of products incorporating the licensed technology in accordance with the terms outlined in the license agreement. The range of royalties on sales of products is between 2.75% – 3.5% and is tiered to achievement of certain sales milestones.
The upfront payment was recognized upon execution of the contract as the performance obligation related to the payment was substantially satisfied. No other milestones or product sales have been achieved as of December 31, 2024.
v3.25.1
Income Taxes
 12 Months Ended
Dec. 31, 2024
Income Tax Disclosure [Abstract]  
Income Taxes Income Taxes
Domestic and international pre-tax income/(loss) consists of the following (in thousands):
Year Ended December 31,
20242023
 United States $(11,141)$5,269 
 International — — 
 (Loss)/Income before income taxes
$(11,141)$5,269 
For the years ended December 31, 2024, and 2023 the Company did not record a tax provision or deferred tax benefit.
Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts for income tax purposes.
Significant components of the Company's deferred tax assets and liabilities are as follows (in thousands):
December 31,
20242023
Deferred tax assets:
Net operating loss
$22,465 $10,170 
Capital loss carryforward
6,922 8 
Credits2,446 2,050 
Capitalized research costs
2,471 443 
Stock based compensation - NQSO
558 — 
Deferred lease liability
127 98 
Accruals and reserves
221 — 
Amortization and patent costs
453 — 
Fixed assets
— 23 
Other8 190 
Gross deferred tax assets35,671 12,982 
Valuation allowance(35,445)(12,842)
Total deferred tax assets226 140 
Deferred tax liabilities:
Fixed assets
(76)— 
Lease ROU asset
(150)(140)
Total deferred tax liabilities(226)(140)
Net deferred tax assets:$— $— 
Management regularly assesses the ability to realize deferred tax assets recorded based upon the weight of available evidence, including such factors as recent earnings history and expected future taxable income on a jurisdiction by jurisdiction basis. In the event that the Company changes its determination as to the amount of realizable deferred tax assets, the Company will adjust its valuation allowance with a corresponding impact to the provision for income taxes in the period in which such determination is made. The Company’s management believes that, based on a number of factors, it is more likely than not, that all or some portion of the deferred tax assets will not be realized; and accordingly, for the year ended December 31, 2024 and 2023 the Company has provided a valuation allowance against the Company’s U.S. net deferred tax assets. The net change in the valuation allowance for the year ended December 31, 2024 was an increase of $22.6 million.
As of December 31, 2024, the Company had U.S. federal net operating loss carryforwards of $87.8 million, which will begin to expire in 2027 and $63.1 million that have an unlimited carryforward period. Additionally, for state income tax purposes, the Company had net operating losses of $56.1 million that will expire at various dates between 2025 and 2043.
As of December 31, 2024, the Company had federal and state capital loss carryforwards of $25 million and $18.7 million respectively. These carryforwards will begin to expire in 2026 through 2029.
As of December 31, 2024, the Company had federal and state research credit carryforwards of approximately $2.9 million and $0.4 million, respectively. The federal research credit carryforwards will begin to expire in 2026 while the California research credits carry forward have an indefinite life.
The Internal Revenue Code of 1986, as amended, imposes restrictions on the utilization of net operating losses in the event of an “ownership change” of a corporation. Accordingly, a company’s ability to use net operating losses may be limited as prescribed under Internal Revenue Code Section 382 (“IRC Section 382”). Events which may cause limitations in the amount of the net operating losses that the Company may use in any one year include, but are not limited to, a cumulative ownership change of more than 50% over a three-year period. Utilization of the federal and state net operating losses may be subject to substantial annual limitation due to the ownership change limitations provided by the IRC Section 382 and similar state provisions. Accordingly, the Merger may constitute an ownership change that may materially limit the company's use of their NOL carryforwards.
As of December 31, 2024 and 2023, the balance of the gross unrecognized tax benefits was $0.1 million each year, with no interest and penalties in either year. The Company estimates that there will be no material changes in its uncertain tax positions in the next 12 months. The Company's policy is to recognize interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense.
The Company files income tax returns in the U.S. federal and various state with varying statutes of limitations. The Company is generally no longer subject to tax examinations for years prior to December 31, 2020 for federal purposes and for state purposes, except in certain limited circumstances.
Rate Reconciliation
Income tax expense differed from the amount computed by applying the federal statutory income tax rate of 21% to pretax income for the years ended December 31, 2024 and 2023 as a result of the following (in thousands):

Year Ended December 31,
20242023
Federal tax at statutory rate$(2,340)$1,107 
State income taxes(724)(46)
Stock based compensation— 5 
Nondeductible items
(4,327)(1,818)
Acquired NOLs(10,353)— 
Acquired capital loss
(3,120)— 
Other items
(1,739)— 
Valuation allowance22,603 752 
Total$— $— 
Uncertain Tax Positions
The Company has established a reserve against its U.S. research and development credits, with no related accrued interest. The Company does not believe it is reasonably possible that its unrecognized tax benefits will significantly change in the next twelve months.
A reconciliation of beginning and ending balances for unrecognized tax benefits is as follows (in thousands):
Balance at December 31, 2023
$— 
Increase in balance upon Merger
264 
Increase in balance related to tax positions taken during prior years 552 
Balance at December 31, 2024
$816 
v3.25.1
Commitments and Contingencies
 12 Months Ended
Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]  
Commitments and Contingencies Commitments and Contingencies
Facilities and Equipment Lease Agreements
The Company leases its lab and office facilities in Huntsville, Alabama, for various terms under long-term, non-cancelable operating lease agreements. The leases expire on various dates from October 2025 through January 2028 and provide for renewal periods of two years.
The Company also leased laboratory equipment under a long-term, non-cancelable operating lease which expired in September 2024 and was subsequently replaced by a month-to-month cancellable agreement.
The Company also leases two pieces of equipment for various terms under long-term, non-cancelable finance lease agreements. One of the two finance leases expired in September 2024 with ownership passed on to the Company in accordance with the original term of the lease agreement, while the other finance lease expired in February 2025.
Supplemental cash flow information related to leases is as follows (in thousands):
Years Ended December 31,
20242023
Cash paid for amounts included in the measurement of lease liabilities:  
Operating cash flows from operating leases$214 $188 
Operating cash flows from finance leases$2 $7 
Financing cash flows from finance leases$35 $48 
Right-of-use assets obtained in exchange for lease obligations  
Operating leases$— $755 
Finance leases$— $— 
Supplemental balance sheet information related to leases was as follows (in thousands other than weighted average remaining lease term and discount rates):
December 31,
20242023
Operating lease  
Right-of-use assets$862 $862 
Accumulated amortization(401)(196)
Right-of-use asset, net$461 $666 
  
Right-of-use lease liability, current$192 $214 
Right-of-use lease liability, noncurrent268 461 
Total operating lease liabilities$460 $675 
  
Finance leases  
Right-of-use assets$163 $163 
Accumulated amortization(77)(53)
Right-of-use asset, net$86 $110 
  
Right-of-use lease liability, current$1 $36 
Right-of-use lease liability, noncurrent— 1 
Total finance lease liabilities
$1 $37 
  
Weighted average remaining lease term  
Operating lease2.53 years3.32 years
Finance leases0.16 years0.64 years
  
Weighted average discount rate  
Operating lease6.67 %6.67 %
Finance leases6.67 %11.90 %
The following is a maturity analysis of the annual undiscounted cash flows of the operating lease liabilities as of December 31, 2024 (in thousands):
 Operating Leases
Year ending December 31, 2025$217 
Year ending December 31, 2026159 
Year ending December 31, 2027117 
Year ending December 31, 202810 
Total undiscounted lease payments503 
Less: imputed interest(43)
Total lease obligations460 
Less: current portion(192)
Long-term lease obligations$268 
Litigation – General
The Company is subject to various claims and contingencies in the ordinary course of its business, including those related to litigation, business transactions, employee-related matters, and others. When the Company is aware of a claim or potential claim, it assesses the likelihood of any loss or exposure. If it is probable that a loss will result and the amount of the loss can be reasonably estimated, the Company will record a liability for the loss. If the loss is not probable or the amount of the loss cannot be reasonably estimated, the Company discloses the claim if the likelihood of a potential loss is reasonably possible and the amount involved could be material. The Company is not aware of any claims likely to have a material adverse effect on its financial condition or results of operations.
Tax Filings
The Company's tax filings are subject to audit by taxing authorities in jurisdictions where it conducts business. These audits may result in assessments of additional taxes that are subsequently resolved with the authorities or potentially through the courts. Management believes the Company has adequately provided for any ultimate amounts that are likely to result from these audits; however, final assessments, if any, could be significantly different than the amounts recorded in the consolidated financial statements.
Employment Contracts
The Company has entered into employment contracts with certain executive officers. Under the provisions of the contracts, the Company may be required to incur severance obligations for matters relating to changes in control, as defined, and involuntary terminations.
Partnership with Enable
During May 2024, the Company entered into a partnership with Enable Injections, Inc. (“Enable”), a healthcare innovation company developing and manufacturing the enFuse® wearable drug delivery to develop and commercialize SER-252 (POZ-apomorphine) in combination with enFuse for the treatment of Parkinson’s disease. The Company will develop and commercialize SER-252 (POZ-apomorphine) in combination with enFuseTM for the treatment of Parkinson’s disease. The enFuseTM wearable technology from Enable is designed to overcome both IV infusion and other subcutaneous administration method shortcomings through fast, simple, and convenient delivery, benefiting patients, providers, as well as payers, with the ability for at home self-administration. The Company anticipates submission of an Investigational New Drug (IND) application to the U.S. Food and Drug Administration with plans to initiate a Phase 1 clinical trial in advanced Parkinson’s disease patients in 2025. The Company paid $2.0 million in May 2024 for the Enable arrangement and will amortize the cost on a straight-line basis until December 2025.
Indemnification
In the normal course of business, the Company may provide indemnifications of varying scope under the Company’s agreements with other companies or consultants, typically for the Company’s research and development programs. Pursuant to these agreements, the Company will generally agree to indemnify, hold harmless, and reimburse the indemnified parties for losses and expenses suffered or incurred by the indemnified parties arising from claims of third parties in connection with the Company’s research and development. Indemnification provisions could also cover third-party infringement claims with respect to patent rights, copyrights, or other intellectual property licensed from the Company to third parties. Office and laboratory leases will also generally indemnify the lessor with respect to certain matters that may arise during the term of the lease. The Registration Rights Agreement between Juvenescence and the Company includes indemnification provisions pursuant to which the parties will indemnify each other from certain liabilities in connection with the registration, offer, and sale of securities under a registration statement, including liabilities arising under the Securities Act. The Company has also agreed to provide the AST Indemnity and the ETC Indemnity pursuant to the Letter of Indemnification described in Note 4, Related Party Transactions. The term of these indemnification obligations will generally continue in effect after the termination or expiration of the particular license, lease, or agreement to which they relate. The potential future payments the Company could be required to make under these indemnification agreements will generally not be subject to any specified maximum amount. Historically, the Company has not been subject to any claims or demands for indemnification. The Company also maintains various liability insurance policies that limit the Company’s financial exposure and in the case of the AST Indemnity and the ETC Indemnity the Company has received a cross-indemnity from Juvenescence against all claims, damages, liabilities or losses arising out of the AST Indemnity and the ETC Indemnity. As a result, the Company believes the fair value of these
indemnification agreements is minimal. Accordingly, the Company has not recorded any liabilities for these agreements to date.
v3.25.1
Net Earnings (Loss) Per Common Share
 12 Months Ended
Dec. 31, 2024
Earnings Per Share [Abstract]  
Net Earnings (Loss) Per Common Share Net Earnings (Loss) Per Common Share
Basic and diluted net earnings (loss) per common share attributable to common stockholders is calculated for the periods presented as follows (in thousands, except per share amounts):
 Year Ended December 31,
 20242023
Basic net (loss) earnings per common share allocable to common stockholders
 
NUMERATOR
Net (loss) income(11,207)5,269
Less: net loss attributable to noncontrolling interest66—
Net (loss) earnings attributable to Serina(11,141)5,269
DENOMINATOR
Weighted-average shares of common stock outstanding used to calculate basic net (loss) earnings per common share7,3592,235
 
Basic net (loss) earnings per common share allocable to common stockholders$(1.51)$2.36 
 
Diluted net (loss) earnings per common share allocable to common stockholders
 
NUMERATOR
Net (loss) earnings attributable to Serina(11,141)5,269
Add back: interest on convertible promissory notes—83
Net (loss) earnings allocable to common stockholders(11,141)5,352
DENOMINATOR
Weighted-average shares of common stock outstanding used to calculate basic net (loss) earnings per common share7,3592,235
Add: dilutive effect of stock options— 1,677
Add: dilutive effect of common stock issued for convertible promissory notes——
Add: dilutive effect of redeemable convertible preferred stock—3,439
Weighted-average shares of common stock outstanding used to calculate diluted net (loss) earnings per common share7,3597,351
Diluted net (loss) earnings per common share attributable to common stockholders$(1.51)$0.73 
The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net (loss) earnings per common share because to do so would be anti-dilutive (in thousands):
 December 31,
20242023
Stock options3,221—
Warrants1,997474
Total anti-dilutive securities5,218474
v3.25.1
Segment reporting
 12 Months Ended
Dec. 31, 2024
Segment Reporting [Abstract]  
Segment reporting Segment reporting
The Company has one reportable segment relating to the research and development of its POZ platform. The segment derived its revenues primarily from License revenue. See Note 10, License Revenue, for details.

The Company’s CODM, its Chief Executive Officer and the senior executive leadership team manages the Company’s operations on an integrated basis for the purposes of allocating resources. When evaluating the Company’s financial performance, the CODM regularly reviews total revenues and expenses by specific categories to make informed decisions.
The table below is a summary of the segment profit or loss, including significant segment expenses (in thousands):
Year Ending December 31,
20242023
Revenue$56 $3,153 
Less:
Research and development
Project specific (1)
2,962 698 
Non-Project specific (2)
475 320 
Compensation (3)
3,462 1,212 
Infrastructure Management and Facilities363 27 
Depreciation218 131 
General and administrative
Professional and outside service fees (4)
3,341 846 
Compensation (3)
4,468 1,213 
Infrastructure Management and Facilities339 236 
Merger and Integration related1,476 1,599 
Total operating expenses17,104 6,282 
Loss from operations(17,048)(3,129)
Interest expense(526)(558)
Interest income235 283 
Other income, net6,132 8,673 
Segment and Consolidated Net (Loss)/Income $(11,207)$5,269 

(1) Research and development project specific expenses largely consists of costs incurred to develop the Company's lead product candidate, SER 252 (POZ-apomorphine) as well as expenses incurred to develop other small molecules, RNA-based therapeutics and antibody-based drug conjugates ("ADCs").
(2) Research and development non-project specific expenses mainly consists of laboratory expenses and fees paid to outside services.
(3) Compensation includes employee salary and fringe benefits, stock based compensation and compensation to independent contractors.
(4) General and administrative professional and outside service fees include legal, accounting and audit, board, insurance, and SEC filing fees.
v3.25.1
Subsequent Events
 12 Months Ended
Dec. 31, 2024
Subsequent Events [Abstract]  
Subsequent Events Subsequent Events
None other than reported in Note 7, Stockholders’ Equity/(Deficit).
v3.25.1
Pay vs Performance Disclosure - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Pay vs Performance Disclosure    
Net (loss) income $ (11,141) $ 5,269
v3.25.1
Insider Trading Arrangements
 12 Months Ended
Dec. 31, 2024
Trading Arrangements, by Individual  
Rule 10b5-1 Arrangement Adopted false
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
v3.25.1
Insider Trading Policies and Procedures
 12 Months Ended
Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]  
Insider Trading Policies and Procedures Adopted true
v3.25.1
Cybersecurity Risk Management and Strategy Disclosure
 12 Months Ended
Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]  
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]
We have implemented cybersecurity measures and processes to address and mitigate material risks from cybersecurity threats. We utilize the services of third party providers to develop, maintain, and implement cybersecurity systems and measures designed to protect our information systems from unauthorized access and damage. Our security measures are periodically assessed, tested, and updated. We do not have employees with information technology or cybersecurity expertise and accordingly we obtain an assessment of our cybersecurity systems and measures from a third party provider different from the provider that is primarily responsible for installation, update, and maintenance of information technology and cyber security systems. Our information technology and cybersecurity service providers primarily interface with members of our accounting and finance group. These processes are an integral part of our internal controls and risk management and the results of the third party assessment are reported annually to the Audit Committee along with a report from management on the effectiveness of internal controls.
We are not aware of the occurrence of any cybersecurity incidents that have materially affected or are reasonably likely to materially affect our business strategy, results of operations, or financial condition. However, there can be no assurance that material cybersecurity incidents will not arise or be discovered in the future.
Cybersecurity Risk Management Processes Integrated [Flag] true
Cybersecurity Risk Management Processes Integrated [Text Block]
We have implemented cybersecurity measures and processes to address and mitigate material risks from cybersecurity threats. We utilize the services of third party providers to develop, maintain, and implement cybersecurity systems and measures designed to protect our information systems from unauthorized access and damage. Our security measures are periodically assessed, tested, and updated. We do not have employees with information technology or cybersecurity expertise and accordingly we obtain an assessment of our cybersecurity systems and measures from a third party provider different from the provider that is primarily responsible for installation, update, and maintenance of information technology and cyber security systems. Our information technology and cybersecurity service providers primarily interface with members of our accounting and finance group. These processes are an integral part of our internal controls and risk management and the results of the third party assessment are reported annually to the Audit Committee along with a report from management on the effectiveness of internal controls.
Cybersecurity Risk Management Third Party Engaged [Flag] true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag] true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag] false
Cybersecurity Risk Board of Directors Oversight [Text Block] These processes are an integral part of our internal controls and risk management and the results of the third party assessment are reported annually to the Audit Committee along with a report from management on the effectiveness of internal controls.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block] accounting and finance group
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block] These processes are an integral part of our internal controls and risk management and the results of the third party assessment are reported annually to the Audit Committee along with a report from management on the effectiveness of internal controls.
Cybersecurity Risk Role of Management [Text Block] Our information technology and cybersecurity service providers primarily interface with members of our accounting and finance group.
Cybersecurity Risk Management Positions or Committees Responsible [Flag] true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block] Our information technology and cybersecurity service providers primarily interface with members of our accounting and finance group.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block] We do not have employees with information technology or cybersecurity expertise and accordingly we obtain an assessment of our cybersecurity systems and measures from a third party provider different from the provider that is primarily responsible for installation, update, and maintenance of information technology and cyber security systems.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block] These processes are an integral part of our internal controls and risk management and the results of the third party assessment are reported annually to the Audit Committee along with a report from management on the effectiveness of internal controls.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag] true
v3.25.1
Summary of Significant Accounting Policies (Policies)
 12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]  
Principles of consolidation
Principles of consolidation
The consolidated financial statements include the accounts of the Company and its subsidiaries in which the Company has a controlling financial interest. For consolidated entities where the Company has less than 100% of ownership, the Company records net loss attributable to noncontrolling interest on the consolidated statement of operations equal to the percentage of the ownership interest retained in such entities by the respective noncontrolling parties. The noncontrolling interest is reflected as a separate element of stockholders’ equity (deficit) on the Company’s consolidated balance sheets. Any material intercompany transactions and balances have been eliminated upon consolidation.
The Company assesses whether it is the primary beneficiary of a variable interest entity (“VIE”) at the inception of the arrangement and at each reporting date. This assessment is based on its power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and the Company’s obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. If the entity is within the scope of the variable interest model and meets the definition of a VIE, the Company considers whether it must consolidate the VIE or provide additional disclosures regarding its involvement with the VIE. If the Company determines that it is the primary beneficiary of the VIE, the Company will consolidate the VIE. This analysis is performed at the initial investment in the entity or upon any reconsideration event. For entities the Company holds as an equity investment that are not consolidated under the VIE model, the Company will consider whether its investment constitutes a controlling financial interest in the entity and therefore should be considered for consolidation under the voting interest model.
The Company had five subsidiaries: Legacy Serina and UniverXome, which are wholly-owned subsidiaries, and ReCyte Therapeutics, Inc. (“ReCyte”), Reverse Bioengineering, Inc. (“Reverse Bio”), and NeuroAirmid Therapeutics, Inc. (“NeuroAirmid”). Prior to the Merger, on March 26, 2024, pursuant to the Merger Agreement, the Company contributed all of its stock in Reverse Bio and ReCyte, along with substantially all of the assets (other than the stock of NeuroAirmid) of the Company to UniverXome. In exchange for the contribution of those assets, UniverXome assumed certain liabilities, including all of the Company’s indebtedness to Juvenescence. UniverXome owns 94.8% of the outstanding capital stock of
ReCyte. ReCyte owns certain pre-clinical research and development assets involving stem cell-derived endothelial and cardiovascular related progenitor cells for the treatment of vascular disorders and ischemic conditions. The Company owned 100% of the outstanding capital of Reverse Bio through UniverXome. Reverse Bio owns assets involved in partial cellular reprogramming using its iTR™ technology with the intent to revert aged or diseased cells to a healthy and functional state. Following the Merger, the Company is primarily focused on developing Legacy Serina’s product candidates which are described elsewhere in this Report.
NeuroAirmid is jointly owned by the Company and certain researchers from the University of California and was organized to pursue certain cell therapies, focusing initially on Huntington’s Disease. The Company owns 47.5% of the outstanding capital stock of NeuroAirmid. The Company consolidates NeuroAirmid despite not having majority ownership interest as it has the ability to influence decision making and financial results through contractual rights and obligations as per Accounting Standards Codification (“ASC”) 810, Consolidation. On March 27, 2024, the Board of Directors of the Company formed a special committee for the purpose of exploring strategic alternatives for the business, assets and/or stock of UniverXome, Reverse Bio, ReCyte and NeuroAirmid
Revision of prior period financial statements
Revision of prior period financial statements
A revision was made to correct the accounting for the recapitalization resulting from the Merger. The adjustment recorded increased additional paid-in capital by $19.8 million with a corresponding decrease to accumulated deficit as of the Merger date. An adjustment was also made to retrospectively reduce the par value of common stock to $0.0001 per share with a corresponding increase to additional paid-in capital. See Note 3, Recapitalization for details. In accordance with Staff Accounting Bulletin No. 99, Materiality, management has concluded that the adjustments are not material to its previously issued financial statements for the periods noted below. Management corrected these out-of-period adjustments in the current period within the consolidated balance sheets and consolidated statements of redeemable convertible preferred stock and stockholders' equity/(deficit) as of December 31, 2024. The following tables summarize the impact of each of the previous reporting periods impacted (amounts reflected in thousands).

A summary of the revisions as of December 31, 2023 is as follows:

Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Common Stock
$25 $(25)$— 
Additional paid-in capital$858 $25 $883 

A summary of the revisions as of March 31, 2024 is as follows:

Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Additional paid-in capital$— $19,803 $19,803 
Accumulated deficit$(28,389)$(19,803)$(48,192)

A summary of the revisions as of June 30, 2024 is as follows:

Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Additional paid-in capital$6,821 $19,803 $26,624 
Accumulated deficit$(23,185)$(19,803)$(42,988)

A summary of the revisions as of September 30, 2024 is as follows:
Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Additional paid-in capital$8,000 $19,803 $27,803 
Accumulated deficit$(21,775)$(19,803)$(41,578)
Financial Statement Reclassification
Financial statement reclassification
Certain account balances from prior periods have been reclassified in these consolidated financial statements to conform to current period classifications. Accounts payable and accrued expenses, previously presented as one line item on the consolidated balance sheet, are now presented separately given the materiality of the balances. The current portion of operating and finance lease liabilities were also reclassified to other current liabilities. Additionally, the non-cash interest expense on convertible promissory note, previously combined with accrued expenses in the operating activities section of the consolidated statement of cash flows, is now presented separately within operating activities. These reclassifications had no effect on the reported results of operations or financial position.
Use of estimates
Use of estimates
The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and (ii) the reported amounts of revenues and expenses during the reporting period, in each case with consideration given to materiality. Significant estimates and assumptions which are subject to significant judgment include those related to assumptions used to value stock-based awards and liability classified warrants. Actual results could differ materially from those estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected.
Concentration of credit risk and other risks and uncertainties
Concentration of credit risk and other risks and uncertainties
Financial instruments that potentially subject the Company to concentrations of risk consist principally of cash equivalents. The Company maintains its cash deposits in Federal Deposit Insurance Corporation (“FDIC”) insured financial institutions and may at times hold investments at Securities Investor Protection Corporation (“SIPC”) insured broker-dealers.
The balances in these accounts may be in excess of FDIC and SIPC insured limits. At December 31, 2024 and 2023, cash and cash equivalents deposits in excess of FDIC limits were nominal and zero, respectively, and investments and deposits in excess of SIPC limits were $2.9 million and $7.3 million, respectively.
Product candidates developed by the Company and its subsidiaries will require approvals or clearances from the United States Food and Drug Administration (“FDA”) or foreign regulatory agencies prior to commercial sales. There can be no assurance that any of the product candidates being developed or planned to be developed by the Company or its subsidiaries will receive any of the required approvals or clearances. If regulatory approval or clearance were to be denied or any such approval or clearance was to be delayed, it would have a material adverse impact on the Company.
Fair value measurements of financial instruments
Fair value measurements of financial instruments
The Company has adopted ASC Topic 820, Fair Value Measurement, for certain financial instruments measured as fair value on a recurring basis. ASC Topic 820 defines fair value, establishes a framework for measuring fair value in accordance with accounting principles generally accepted in the United States, and expands disclosures about fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. ASC Topic 820 establishes a three-tier fair value hierarchy which prioritizes the inputs used in measuring fair value.
The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (level 1 measurements) and the lowest priority to unobservable inputs (level 3 measurements).
The three levels of inputs that may be used to measure fair value are as follows:
•Level 1: Quoted prices in active markets for identical assets or liabilities.
•Level 2: Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets with insufficient volume or infrequent transactions (less active markets), or model-derived valuations in which all significant inputs are observable or can be derived principally from or corroborated with
observable market data for substantially the full term of the assets or liabilities. Level 2 inputs also include non-binding market consensus prices that can be corroborated with observable market data, as well as quoted prices that were adjusted for security-specific restrictions.
•Level 3: Unobservable inputs to the valuation methodology are significant to the measurement of the fair value of assets or liabilities. Level 3 inputs also include non-binding market consensus prices or non-binding broker quotes that we were unable to corroborate with observable market data.
The Company has elected to measure the convertible promissory notes at fair value on a recurring basis. Changes in fair value are recorded in other income, net, on the consolidated statements of operation . Interest accrued on the notes is reflected in interest expense on the consolidated statement of operations.
Cash and cash equivalents
Cash and cash equivalents
Cash and cash equivalents include unrestricted cash and all highly liquid instruments with original maturities of three months or less at the date of purchase. Cash equivalents consist primarily of amounts invested in money market accounts.
Property and equipment, net
Property and equipment, net
Property and equipment are carried at cost less accumulated depreciation. The costs of additions and betterments are capitalized and expenditures for repairs and maintenance are expensed as incurred. When items of property and equipment are sold or retired, the related costs and accumulated depreciation are removed from the accounts and any gain or loss is included in the consolidated statements of operations. Depreciation of property and equipment is provided utilizing the straight-line method over the range of lives used of the respective assets, which is 3 - 10 years
Leases
Leases
The Company determines if an arrangement is a lease at inception. Leases are classified as either finance or operating, with classification affecting the pattern of expense recognition in the consolidated statements of operations. The Company recognizes right-of-use (“ROU”) assets and lease liabilities for leases with terms greater than twelve months in the consolidated balance sheet.
ROU assets represent an entity’s right to use an underlying asset during the lease term and lease liabilities represent an entity’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. If the lease agreement does not provide an implicit rate in the contract, the lessee uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives. For such purposes, the lease term applied may include options to extend or terminate the lease when it is reasonably certain that the Company or a subsidiary will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term.
The Company has elected to combine lease and non-lease components as a single component. Operating leases are recognized on the consolidated balance sheet as ROU lease assets, current lease liabilities, and non-current lease liabilities. Fixed lease payments are included in the calculation of the lease balances, while variable costs paid for certain operating and pass through costs are excluded. The Company's finance leases are not material.
Intangible assets, net
Intangible assets, net
Intangible assets, consisting primarily of acquired in-process research and development (“IPR&D”) with alternative future use and patents, are stated at acquired cost, less accumulated amortization. Amortization expense is computed using the straight-line method over the estimated useful life of 10 years. The Company's intangible assets were acquired as a result of the merger closing between Age-X and Serina and were sold in connection with the sale of UniverXome to Juvenescence in December 2024. Amortization expense was $0.1 million for the year ended December 31, 2024.
Impairment of long-lived assets
Impairment of long-lived assets
The Company assesses the impairment of long-lived assets whenever events or changes in circumstances indicate that such assets might be impaired and the carrying value may not be recoverable. If events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable and the expected undiscounted future cash flows attributable to the asset are less than the carrying amount of the asset, an impairment loss, equal to the excess of the carrying value of the
asset over its fair value, is recorded. There has been no impairment of long-lived assets for the accounting periods presented.
Accounting for warrants
Accounting for warrants
The Company determines the accounting classification of warrants it issues, as either liability or equity, by first assessing whether the warrants meet liability classification in accordance with ASC 480-10, Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity, then in accordance with ASC 815-40, Accounting for Derivative Financial Instruments Indexed to, and Potentially Settled in, a Company’s Own Stock. Under ASC 480, warrants are considered liability classified if the warrants are mandatorily redeemable, obligate the Company to settle the warrants or the underlying shares by paying cash or other assets, or warrants that must or may require settlement by issuing a variable number of shares. If warrants do not meet liability classification under ASC 480-10, the Company assesses the requirements under ASC 815-40, which states that contracts that require or may require the issuer to settle the contract for cash are liabilities recorded at fair value, irrespective of the likelihood of the transaction occurring that triggers the net cash settlement feature. If the warrants do not require liability classification under ASC 815-40, and in order to conclude equity classification, the Company also assesses whether the warrants are indexed to its common stock and whether the warrants are classified as equity under ASC 815-40 or other applicable U.S. GAAP. After all relevant assessments, the Company concludes whether the warrants are classified as liability or equity. Liability classified warrants are recorded at fair value upon issuance and subsequently remeasured to fair value each reporting period until settlement with all changes in fair value recorded in the consolidated statements of operations. Equity classified warrants are recorded at fair value upon issuance and are not subsequently remeasured. See Note 5, Related Party Transactions and 6, Fair Value Measurements, for additional information regarding warrants.
Redeemable convertible preferred stock
Redeemable convertible preferred stock
The Company recorded redeemable convertible preferred stock at fair value upon issuance, net of any issuance costs. As of December 31, 2023, the Company's preferred stock that was redeemable in circumstances not within the Company’s control was classified outside of permanent equity. The redeemable preferred stock was converted into common stock on March 26, 2024 upon consummation of the Merger.
Revenue Recognition
Revenue recognition
License revenues
The Company's license revenue relates to a non-exclusive license agreement entered into with Pfizer, Inc. in 2023 that was determined to be within the scope of ASC 606, Revenue From Contracts with Customers. As consideration for the agreement, the Company received an upfront payment and is eligible to receive future payments upon achievement of certain milestones as well as royalties on future sales of products developed using the licensed technology. As the Company's performance obligations were substantially completed upon transfer of the license, the upfront payment was recognized as revenue when earned. Milestone payments were not included in the initial transaction price as it was probable that a significant reversal of cumulative revenue would occur due to the uncertainty in achievement of such milestones. The milestone payments will be recognized as revenue when achievement of the specified milestones is probable. Royalty payments will be recognized as revenue when earned.
Grant revenues
Grant revenues
The Company receives government grants that reimburse the Company for certain allowable costs for funded projects. Grant revenue is recognized in the consolidated statement of operations on a systematic basis over the period in which the Company recognizes qualified research and development costs that grant is intended to compensate and there is reasonable assurance that the Company will meet the terms and conditions of the grant.
Grant revenues for the years ended December 31, 2024 and 2023 were not material.
Research and Development Expense
Research and development expense
Research and development costs are expensed as they are incurred and primary consist of cost incurred for the development of product candidates and drug discovery efforts, which include personnel costs consisting of salaries, benefits and equity-based compensation expense; expenses incurred under agreements with consultants and contract organizations that conduct research and development activities on the Company's' behalf; costs related to production of preclinical and clinical
materials, including fees paid to contract manufacturers; laboratory and vendor expenses related to the execution of preclinical studies and planned clinical trials; and laboratory supplies and equipment used for internal research and development activities. The Company continually evaluates new product opportunities and engages in intensive research and product development efforts. Research and development expenses include both direct costs tied to a specific contract or grant, and indirect costs. Research and development expenses incurred and reimbursed by grants from third parties or governmental agencies, if any and as applicable, approximate the respective revenues recognized in the consolidated statements of operations.
General and Administrative Expense
General and administrative expense
General and administrative expenses consist primarily of personnel costs, and other expenses for outside professional services, including legal, recruiting, audit and accounting, and facility related costs not otherwise included in research and development expenses. Personnel costs consist of salaries, benefits and equity-based compensation expense for personnel in executive and other administrative functions.
Income taxes
Income taxes
Income taxes are provided in accordance with ASC Topic 740, which prescribes the use of the asset and liability method, whereby deferred tax asset or liability account balances are calculated at the balance sheet date using current tax laws and rates in effect. Valuation allowances are established when necessary to reduce deferred tax assets when it is more likely than not that a portion or all of the deferred tax assets will not be realized. ASC 740 guidance also prescribes a recognition threshold and a measurement attribute for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For benefits to be recognized, a tax position must be more-likely-than-not sustainable upon examination by taxing authorities. Deferred taxes represent the future tax return consequences of those differences, which will either be taxable or deductible when the assets and liabilities are recovered or settled. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which the differences are expected to be recovered or settled.
The Company only recognizes tax benefits from an uncertain tax position if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position are measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate resolution. To date, the Company has not recognized such tax benefits in its financial statements.
Stock-based compensation expense
Stock-based compensation expense
The Company provides share-based payments in the form of stock options and restricted stock awards. For awards only subject to service conditions, the Company uses the straight-line attribution method for recognizing compensation expense over the requisite service period, which is generally the vesting period of the award. Compensation expense is recognized on awards ultimately expected to vest. Forfeitures are recorded when they occur.

The Company estimates the fair value of stock option awards and restricted stock awards on the grant date using a Black-Scholes option pricing model.
Basic and diluted net earnings (loss) per share attributable to common stockholders
Basic and diluted net earnings (loss) per share attributable to common stockholders
The Company follows the two-class method when computing net loss per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net loss per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. The Company’s redeemable convertible preferred stock contractually entitles the holders of such shares to participate in dividends but does not contractually require the holders of such shares to participate in losses of the Company.
Basic earnings (loss) per share (“EPS”) of common stock is computed by dividing net income (loss) available to common stockholders (numerator) by the weighted average number of shares of common stock outstanding (denominator) during the period.
Diluted EPS gives effect to all dilutive potential common shares outstanding during the period using the treasury stock method for stock options and warrants and the if-converted method for redeemable convertible preferred stock and convertible promissory notes. In computing diluted EPS, the average stock price for the period is used to determine the number of shares assumed to be purchased from the exercise of stock options and/or warrants. Diluted EPS excludes all dilutive potential shares if their effect is anti-dilutive.
Segment Reporting
Segment reporting
Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the Chief Operating Decision Maker (the “CODM”), the Chief Executive Officer, in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating and reporting segment in the United States.
Recently adopted accounting pronouncements
Recently adopted accounting pronouncements
In November 2023, the FASB issued Accounting Standards Update ("ASU") 2023-07, Segment Reporting (Topic 280)— Improvements to Reportable Segment Disclosures, which improves segment disclosure requirements, primarily through enhanced disclosure requirements for significant segment expenses. The improved disclosure requirements apply to all public entities that are required to report segment information, including those with only one reportable segment. The Company adopted as of January 1, 2024. There was no impact on the Company’s reportable segments identified and additional required disclosures have been included in Note 13.
In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740)—Improvements to income Tax Disclosures, under which entities must consistently categorize and provide greater disaggregation of information in the rate reconciliation. They must also further disaggregate income taxes paid. ASU 2023-09 enhances annual income tax disclosures to address investor requests for more information about the tax risks and opportunities present in an entity’s worldwide operations. The Company will adopt this standard as of January 1, 2025, adoption is not expected to have a material impact on the consolidated financial statements.
Recently Issued Accounting Pronouncements Not Yet Adopted
Recently issued accounting pronouncements not yet adopted
In March 2024, the FASB issued ASU 2024-02, Codification Improvements—Amendments to Remove References to the Concepts Statements. ASU 2024-02 removes various references to the FASB’s Concepts Statements from the FASB’s Codification. The Concepts Statements are non-authoritative guidance issued by the FASB that provide the objectives, qualitative characteristics and other concepts that govern the development of accounting principles by the FASB. The ASU indicates that the goal of the amendments is to simplify the Codification and distinguish between nonauthoritative and authoritative guidance (since, unlike the Codification, the concepts statements are nonauthoritative). This ASU is effective for the Company beginning January 1, 2025 and is not expected to have a material impact on the consolidated financial statements.
In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses to improve disclosures by providing more detailed information about the types of expenses in commonly presented expense captions. The guidance is effective for annual reporting periods beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the effect this standard will have on its consolidated financial statements and related disclosures.
v3.25.1
Summary of Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]  
Schedule of Error Corrections and Prior Period Adjustments
A summary of the revisions as of December 31, 2023 is as follows:

Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Common Stock
$25 $(25)$— 
Additional paid-in capital$858 $25 $883 

A summary of the revisions as of March 31, 2024 is as follows:

Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Additional paid-in capital$— $19,803 $19,803 
Accumulated deficit$(28,389)$(19,803)$(48,192)

A summary of the revisions as of June 30, 2024 is as follows:

Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Additional paid-in capital$6,821 $19,803 $26,624 
Accumulated deficit$(23,185)$(19,803)$(42,988)

A summary of the revisions as of September 30, 2024 is as follows:
Consolidated Balance Sheet
As Filed
AdjustmentsAs Revised
Additional paid-in capital$8,000 $19,803 $27,803 
Accumulated deficit$(21,775)$(19,803)$(41,578)
v3.25.1
Recapitalization (Tables)
 12 Months Ended
Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]  
Schedule Of Reverse Recapitalization See table below representing the shares outstanding immediately following the effective time of the Merger.
Total AgeX shares outstanding prior to Merger2,500,612
Shares issued to Legacy Serina stockholders5,913,277
Total shares outstanding8,413,889
As part of the recapitalization, the Company obtained the assets and liabilities listed below (in thousands):
Cash and cash equivalents$337 
Other current assets174 
Intangible assets576 
Accounts payable and accrued expenses(2,830)
Loan payable to Juvenescence(8,017)
Net liabilities acquired
(9,760)
Conversion of AgeX-Serina Note
10,721 
Total$961 
v3.25.1
Selected Balance Sheet Components (Tables)
 12 Months Ended
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Schedule of Prepaid Expenses and Other Current Assets
Prepaid expenses and other current assets were as follows (in thousands):
December 31,
 20242023
Prepaid technology access fee$1,333 $— 
Prepaid insurance192 — 
Other prepaid expenses402 — 
Other current assets77 — 
Total prepaid expenses and other current assets$2,004 $— 
Schedule of Property and Equipment, Net
Property and equipment, net was as follows (in thousands):
December 31,
20242023
Computer equipment$— $30 
Equipment966 837 
Software136 96 
Total property and equipment, gross1,102 963 
Less: accumulated depreciation and amortization(601)(390)
Total property and equipment, net$501 $573 
Schedule of Accrued Liabilities
Accrued liabilities were comprised of the following (in thousands):
December 31,
20242023
Accrued severance$304 $— 
Accrued interest on convertible promissory notes— 558 
Accrued compensation559 13 
Other accrued expenses566 12 
Total accrued expenses$1,429 $583 
v3.25.1
Fair Value Measurements (Tables)
 12 Months Ended
Dec. 31, 2024
Fair Value Disclosures [Abstract]  
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis
The Company had the following liabilities measured at fair value on a recurring basis (in thousands):
Balance at December 31, 2024Level 1Level 2Level 3
Liabilities:    
Warrant liability$3,582 $— $— $3,582 
Total$3,582 $— $— $3,582 
Balance at December 31, 2023Level 1Level 2Level 3
Liabilities:
Convertible promissory notes$2,983 $— $— $2,983 
Total$2,983 $— $— $2,983 
Schedule of Convertible Promissory Note Liabilities Measured at Fair Value on Recurring Basis
The following is a reconciliation of the beginning and ending balances for the AgeX-Serina Note and the Legacy Serina Convertible Notes liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the years ended December 31, 2024 and 2023, respectively (in thousands):
 AgeX-Serina
Note 		 Legacy Serina
Convertible Notes
Balance as of December 31, 2023$2,983 $— 
Conversion into equity(10,000)— 
Change in fair value7,017 — 
Balance as of December 31, 2024$— $— 
 AgeX-Serina
Note 		Legacy Serina
Convertible Notes
Balance as of December 31, 2022$— $1,617 
Convertible debt issuance10,000 100 
Inception adjustment(2,240)— 
Notes converted to Series A-5 pref. stock— (963)
Notes converted to warrants— (175)
Change in fair value(4,777)(579)
Balance as of December 31, 2023$2,983 $— 
Schedule of Warrant Liability Measured at Fair Value on Recurring Basis
The following is a reconciliation of the beginning and ending balances of warrant liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the year ended December 31, 2024 (in thousands):

Merger Warrants
Balance as of December 31, 2023$— 
Fair value at inception of Post-Merger Warrants 18,501 
Exercise(1,372)
Derecognition of Incentive Warrants(1,798)
Initial recognition of fair value of Replacement Incentive Warrants
1,407 
Change in fair value(13,156)
Balance at December 31, 2024$3,582 
There were no warrant liabilities for the year ended December 31, 2023.
Schedule of Estimates the Fair Value of Warrants
The Company estimates the fair value of warrants using the Black-Scholes-Merton option pricing model with the following assumptions during the year ended December 31, 2024:

Merger Warrants
Expected volatility
99.15% -125.89%
Expected term (in years)
0.6 – 3.24
Risk-free interest rate
4.14% - 4.28%
Expected dividend yield0.00 %
v3.25.1
Stockholders’ Equity/(Deficit) (Tables)
 12 Months Ended
Dec. 31, 2024
Class of Warrant or Right [Line Items]  
Schedule of Redeemable Convertible Preferred Stock
The table below presents Legacy Serina redeemable convertible preferred stock information adjusted for the 0.97682654 Exchange Ratio as of December 31, 2023 (in thousands other than per share price).
Preference OrderDesignationShares
Designated		Shares
Issued and
Outstanding		Issue Price
per Share		Carrying ValueLiquidation Preference
#1Series A Preferred Stock391391$5.12 $2,000 $2,002 
#2Series A-1 Preferred Stock2932936.82 1,998 1,998 
#3Series A-2 Preferred Stock1,0911,09110.17 11,085 11,095 
#4Series A-3 Preferred Stock48748712.80 6,240 6,234 
#5Series A-4 Preferred Stock70270213.31 9,347 9,344 
#6Series A-5 Preferred Stock1,95447413.31 5,734 6,309 
  4,9183,438 $36,404 $36,982 
Schedule of Reserved Common Stock on an As-Converted Basis for Future Issuance
As of December 31, 2024 and 2023, the Company had reserved common stock on an as-converted basis for future issuance as follows (in thousands):
December 31,
20242023
Outstanding common stock warrants
1,997359
Outstanding common stock options under the Plans
3,2211,716
Reserved for future stock option grants
1,97713
Total common stock reserved for future issuance
7,1952,088
Merger Warrants  
Class of Warrant or Right [Line Items]  
Schedule of Warrant Activity
Details of the Merger Warrants activity for the year ended December 31, 2024 are as follows ( in thousands):
Post-Merger Warrants Incentive WarrantsReplacement Incentive Warrants
Balance at December 31, 2023— — — 
Warrants issued1,500 378 — 
Warrants exercised(378)— — 
Warrants exchanged(755)— 756 
Balance at December 31, 2024367 378 756 
v3.25.1
Stock-Based Awards (Tables)
 12 Months Ended
Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]  
Schedule of Stock Option Activity
A summary of Serina stock option activity under all plans and related information are as follows (in thousands, except weighted average exercise price):
Number
of Options
Outstanding		Weighted-
Average
Exercise Price
(per share)		Weighted-Average Remaining Contractual Term
(in years)		Aggregate Intrinsic Value
(in thousands)
Balance at December 31, 20231,716$0.067.5$— 
Assumed options in connection with the Merger12$24.04
Granted1,713$9.03
Exercised(195)$0.06$1,753 
Cancelled/Forfeited(25)$13.59
Balance at December 31, 20243,221$4.817.7$7,530 
Options exercisable December 31, 20241,677$1.056.0$7,530 
Schedule of Stock Based Compensation Expense
Stock-based compensation expense has been allocated to operating expenses as follows (in thousands):
Year ended December 31,
20242023
Research and development$551 $— 
General and administrative2,044 25 
Total stock-based compensation expense$2,595 $25 
Schedule of Weighted Average Assumptions to Calculate Fair Value of Stock Options
The fair value of each option award is estimated on the date of grant using a Black-Scholes option pricing model applying the weighted-average assumptions including the market price of the underlying common stock, expected option life, risk-free interest rates, volatility, and dividend yield. The assumptions that were used to calculate the grant date fair value of employee and non-employee stock option grants for the years ended December 31, 2024 and 2023 were as follows:
Year ended December 31,
2024(1)
2023(2)
Expected life (in years)
5.0 - 6.1
— 
Volatility
112.67% - 118.33%
— 
Risk-free interest rates
3.54% - 4.65%
— 
Dividend yield—— 
(1)Relates to stock options granted under the Serina 2024 Equity Incentive Plan and the Serina 2024 Inducement Equity Plan during the period.
(2)There were no stock options granted during the year.
v3.25.1
Income Taxes (Tables)
 12 Months Ended
Dec. 31, 2024
Income Tax Disclosure [Abstract]  
Schedule of Income (Loss) before Income Tax, Domestic and Foreign
Domestic and international pre-tax income/(loss) consists of the following (in thousands):
Year Ended December 31,
20242023
 United States $(11,141)$5,269 
 International — — 
 (Loss)/Income before income taxes
$(11,141)$5,269 
Schedule of Components of Deferred Tax Assets and Liabilities
Significant components of the Company's deferred tax assets and liabilities are as follows (in thousands):
December 31,
20242023
Deferred tax assets:
Net operating loss
$22,465 $10,170 
Capital loss carryforward
6,922 8 
Credits2,446 2,050 
Capitalized research costs
2,471 443 
Stock based compensation - NQSO
558 — 
Deferred lease liability
127 98 
Accruals and reserves
221 — 
Amortization and patent costs
453 — 
Fixed assets
— 23 
Other8 190 
Gross deferred tax assets35,671 12,982 
Valuation allowance(35,445)(12,842)
Total deferred tax assets226 140 
Deferred tax liabilities:
Fixed assets
(76)— 
Lease ROU asset
(150)(140)
Total deferred tax liabilities(226)(140)
Net deferred tax assets:$— $— 
Schedule of Income Tax Rate Reconciliation
Income tax expense differed from the amount computed by applying the federal statutory income tax rate of 21% to pretax income for the years ended December 31, 2024 and 2023 as a result of the following (in thousands):

Year Ended December 31,
20242023
Federal tax at statutory rate$(2,340)$1,107 
State income taxes(724)(46)
Stock based compensation— 5 
Nondeductible items
(4,327)(1,818)
Acquired NOLs(10,353)— 
Acquired capital loss
(3,120)— 
Other items
(1,739)— 
Valuation allowance22,603 752 
Total$— $— 
Schedule of Unrecognized Tax Benefits
A reconciliation of beginning and ending balances for unrecognized tax benefits is as follows (in thousands):
Balance at December 31, 2023
$— 
Increase in balance upon Merger
264 
Increase in balance related to tax positions taken during prior years 552 
Balance at December 31, 2024
$816 
v3.25.1
Commitment and Contingencies (Tables)
 12 Months Ended
Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]  
Schedule Of Cash Flow Supplemental Disclosures Operating And Financing Leases Supplemental cash flow information related to leases is as follows (in thousands):
Years Ended December 31,
20242023
Cash paid for amounts included in the measurement of lease liabilities:  
Operating cash flows from operating leases$214 $188 
Operating cash flows from finance leases$2 $7 
Financing cash flows from finance leases$35 $48 
Right-of-use assets obtained in exchange for lease obligations  
Operating leases$— $755 
Finance leases$— $— 
Schedule Of Supplemental Balance Sheet Information Related To Operating And Financing Leases
Supplemental balance sheet information related to leases was as follows (in thousands other than weighted average remaining lease term and discount rates):
December 31,
20242023
Operating lease  
Right-of-use assets$862 $862 
Accumulated amortization(401)(196)
Right-of-use asset, net$461 $666 
  
Right-of-use lease liability, current$192 $214 
Right-of-use lease liability, noncurrent268 461 
Total operating lease liabilities$460 $675 
  
Finance leases  
Right-of-use assets$163 $163 
Accumulated amortization(77)(53)
Right-of-use asset, net$86 $110 
  
Right-of-use lease liability, current$1 $36 
Right-of-use lease liability, noncurrent— 1 
Total finance lease liabilities
$1 $37 
  
Weighted average remaining lease term  
Operating lease2.53 years3.32 years
Finance leases0.16 years0.64 years
  
Weighted average discount rate  
Operating lease6.67 %6.67 %
Finance leases6.67 %11.90 %
Lessee, Operating Lease, Liability, to be Paid, Maturity
The following is a maturity analysis of the annual undiscounted cash flows of the operating lease liabilities as of December 31, 2024 (in thousands):
 Operating Leases
Year ending December 31, 2025$217 
Year ending December 31, 2026159 
Year ending December 31, 2027117 
Year ending December 31, 202810 
Total undiscounted lease payments503 
Less: imputed interest(43)
Total lease obligations460 
Less: current portion(192)
Long-term lease obligations$268 
v3.25.1
Net Earnings (Loss) Per Common Share (Tables)
 12 Months Ended
Dec. 31, 2024
Earnings Per Share [Abstract]  
Schedule of Basic and Diluted Net Earnings (Loss) Per Common Share Attributable to Common Shareholders
Basic and diluted net earnings (loss) per common share attributable to common stockholders is calculated for the periods presented as follows (in thousands, except per share amounts):
 Year Ended December 31,
 20242023
Basic net (loss) earnings per common share allocable to common stockholders
 
NUMERATOR
Net (loss) income(11,207)5,269
Less: net loss attributable to noncontrolling interest66—
Net (loss) earnings attributable to Serina(11,141)5,269
DENOMINATOR
Weighted-average shares of common stock outstanding used to calculate basic net (loss) earnings per common share7,3592,235
 
Basic net (loss) earnings per common share allocable to common stockholders$(1.51)$2.36 
 
Diluted net (loss) earnings per common share allocable to common stockholders
 
NUMERATOR
Net (loss) earnings attributable to Serina(11,141)5,269
Add back: interest on convertible promissory notes—83
Net (loss) earnings allocable to common stockholders(11,141)5,352
DENOMINATOR
Weighted-average shares of common stock outstanding used to calculate basic net (loss) earnings per common share7,3592,235
Add: dilutive effect of stock options— 1,677
Add: dilutive effect of common stock issued for convertible promissory notes——
Add: dilutive effect of redeemable convertible preferred stock—3,439
Weighted-average shares of common stock outstanding used to calculate diluted net (loss) earnings per common share7,3597,351
Diluted net (loss) earnings per common share attributable to common stockholders$(1.51)$0.73 
Schedule of Diluted Net Earnings (loss) Per Common Share
The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net (loss) earnings per common share because to do so would be anti-dilutive (in thousands):
 December 31,
20242023
Stock options3,221—
Warrants1,997474
Total anti-dilutive securities5,218474
v3.25.1
Segment Reporting (Tables)
 12 Months Ended
Dec. 31, 2024
Segment Reporting [Abstract]  
Schedule of Segment Reporting Information, by Segment
The table below is a summary of the segment profit or loss, including significant segment expenses (in thousands):
Year Ending December 31,
20242023
Revenue$56 $3,153 
Less:
Research and development
Project specific (1)
2,962 698 
Non-Project specific (2)
475 320 
Compensation (3)
3,462 1,212 
Infrastructure Management and Facilities363 27 
Depreciation218 131 
General and administrative
Professional and outside service fees (4)
3,341 846 
Compensation (3)
4,468 1,213 
Infrastructure Management and Facilities339 236 
Merger and Integration related1,476 1,599 
Total operating expenses17,104 6,282 
Loss from operations(17,048)(3,129)
Interest expense(526)(558)
Interest income235 283 
Other income, net6,132 8,673 
Segment and Consolidated Net (Loss)/Income $(11,207)$5,269 

(1) Research and development project specific expenses largely consists of costs incurred to develop the Company's lead product candidate, SER 252 (POZ-apomorphine) as well as expenses incurred to develop other small molecules, RNA-based therapeutics and antibody-based drug conjugates ("ADCs").
(2) Research and development non-project specific expenses mainly consists of laboratory expenses and fees paid to outside services.
(3) Compensation includes employee salary and fringe benefits, stock based compensation and compensation to independent contractors.
(4) General and administrative professional and outside service fees include legal, accounting and audit, board, insurance, and SEC filing fees.
v3.25.1
Organization, Basis of Presentation and Liquidity - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Net (loss) income $ (11,207) $ 5,269
Net cash used in operating activities (17,137) (2,476)
Cash and cash equivalents 3,672 7,619
Expected proceeds from business merger warrant exercises 5,000  
Net (loss) income $ (11,141) $ 5,269
v3.25.1
Summary of Significant Accounting Policies - Narrative (Details)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 15, 2023
USD ($)
Dec. 31, 2024
USD ($)
numberOfSubsidiaries
$ / shares
Dec. 31, 2024
USD ($)
segment
numberOfSubsidiaries
$ / shares
Dec. 31, 2024
USD ($)
numberOfSubsidiaries
numberOfOperatingSegments
$ / shares
Dec. 31, 2023
USD ($)
$ / shares
Mar. 31, 2024
$ / shares
Mar. 26, 2024
$ / shares
Property, Plant and Equipment [Line Items]              
Subsidiaries | numberOfSubsidiaries   5 5 5      
Common stock, par or stated value per share (in usd per share) | $ / shares   $ 0.0001 $ 0.0001 $ 0.0001 $ 0.0001 $ 0.0001 $ 0.0001
Change in fair value of warrants   $ (13,156)     $ (1,077)    
Uninsured amount   0 $ 0 $ 0 0    
Cash, SIPC insured amount   $ 2,900 $ 2,900 $ 2,900 7,300    
Finite-lived intangible asset, useful life (in years)   10 years 10 years 10 years      
Amortization expense of intangible assets   $ 100          
Impairment of long-lived assets   0     0    
Total revenues   56     3,153    
Number of operating segments     1 1      
Number of reportable segments | segment     1        
License revenues              
Property, Plant and Equipment [Line Items]              
Total revenues $ 3,000 $ 0     $ 3,000    
Maximum              
Property, Plant and Equipment [Line Items]              
Property, plant and equipment, useful life ( in years)   10 years 10 years 10 years      
Minimum              
Property, Plant and Equipment [Line Items]              
Property, plant and equipment, useful life ( in years)   3 years 3 years 3 years      
Univer Xome              
Property, Plant and Equipment [Line Items]              
Equity method investment, ownership percentage             94.80%
Reverse Bioengineering Inc              
Property, Plant and Equipment [Line Items]              
Equity method investment, ownership percentage             100.00%
NeuroAirmid Therapeutics Inc              
Property, Plant and Equipment [Line Items]              
Equity method investment, ownership percentage             47.50%
v3.25.1
Summary of Significant Accounting Policies - Revision of Prior Period Financial Statements (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Sep. 30, 2024
Jun. 30, 2024
Mar. 31, 2024
Dec. 31, 2023
Consolidated Balance Sheet          
Common stock $ 1       $ 0
Additional paid-in capital 44,958 $ 27,803 $ 26,624 $ 19,803 883
Accumulated deficit $ (44,318) (41,578) (42,988) (48,192) (33,177)
As Filed          
Consolidated Balance Sheet          
Common stock         25
Additional paid-in capital   8,000 6,821 0 858
Accumulated deficit   (21,775) (23,185) (28,389)  
Adjustments          
Consolidated Balance Sheet          
Common stock         (25)
Additional paid-in capital   19,803 19,803 19,803 $ 25
Accumulated deficit   $ (19,803) $ (19,803) $ (19,803)  
v3.25.1
Recapitalization - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Mar. 26, 2024
Dec. 31, 2023
Dec. 31, 2024
Mar. 31, 2024
Mar. 15, 2023
Recapitalization [Line Items]          
Conversion of stock, shares converted (in shares) 0.97682654        
Common stock, par or stated value per share (in usd per share) $ 0.0001 $ 0.0001 $ 0.0001 $ 0.0001  
AgeX-Serina Note          
Recapitalization [Line Items]          
Convertible debt issuance   $ 10,000      
Convertible Promissory Note          
Recapitalization [Line Items]          
Debt instrument, face amount         $ 10,000
v3.25.1
Recapitalization - Effective Time Of The Merger (Details) - shares
Mar. 26, 2024
Dec. 31, 2024
Dec. 31, 2023
Recapitalization [Line Items]      
Common stock, shares, outstanding (in shares) 8,413,889 9,422,000 2,410,000
AgeX      
Recapitalization [Line Items]      
Common stock, shares, outstanding (in shares) 2,500,612    
Serina Therapeutics Inc      
Recapitalization [Line Items]      
Issuance of stock (in shares) 5,913,277    
v3.25.1
Recapitalization (Details)
$ in Thousands
Mar. 26, 2024
USD ($)
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]  
Cash and cash equivalents $ 337
Other current assets 174
Intangible assets 576
Accounts payable and accrued expenses (2,830)
Accounts payable and accrued expenses (8,017)
Net liabilities acquired 9,760
Conversion of AgeX-Serina Note 10,721
Total $ 961
v3.25.1
Selected Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Prepaid technology access fee $ 1,333 $ 0
Prepaid insurance 192 0
Other prepaid expenses 402 0
Other current assets 77 0
Total prepaid expenses and other current assets $ 2,004 $ 0
v3.25.1
Selected Balance Sheet Components - Schedule of Property and Equipment (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross $ 1,102 $ 963
Less: accumulated depreciation and amortization (601) (390)
Total property and equipment, net 501 573
Computer equipment    
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross 0 30
Equipment    
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross 966 837
Software    
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross $ 136 $ 96
v3.25.1
Selected Balance Sheet Components - Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Offsetting [Abstract]    
Depreciation and amortization $ 0.1 $ 0.1
v3.25.1
Selected Balance Sheet Components - Schedule of Accrued Liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Accrued severance $ 304 $ 0
Accrued interest on convertible promissory notes 0 558
Accrued compensation 559 13
Other accrued expenses 566 12
Total accrued expenses $ 1,429 $ 583
v3.25.1
Related Party Transactions - Narrative (Details)
$ / shares in Units, $ in Millions
 1 Months Ended 12 Months Ended
Oct. 15, 2024
USD ($)
May 08, 2024
USD ($)
Mar. 26, 2024
USD ($)
Mar. 14, 2024
Nov. 09, 2023
USD ($)
Jul. 31, 2023
USD ($)
May 09, 2023
USD ($)
Mar. 13, 2023
USD ($)
Feb. 09, 2023
USD ($)
Feb. 14, 2022
USD ($)
Jul. 31, 2023
USD ($)
Dec. 31, 2024
USD ($)
$ / shares
shares
Dec. 31, 2023
USD ($)
$ / shares
shares
Dec. 21, 2023
shares
Dec. 31, 2022
Warrant purchase (in shares) | shares                         53,980    
Stockholders' equity note, stock split, conversion ratio       0.02843332                      
Gain (loss) in subsidiary                       $ (10.9)      
Univer Xome                              
Secured debt assumed                       11.3      
Intangible assets                       0.5      
Secured Convertible Promissory Note | Secured Debt                              
Line of credit facility, current borrowing capacity           $ 16.7         $ 16.7        
Debt instrument, decrease, forgiveness                     18.0        
Loan processing fee                     1.3        
2022 Warrants                              
Percentage of each draw of loan funds                             50.00%
2022 Warrants | Minimum                              
Warrant, exercise price, increase (in usd per share) | $ / shares                         $ 20.75    
2022 Warrants | Maximum                              
Warrant, exercise price, increase (in usd per share) | $ / shares                         $ 30.94    
2022 Secured Convertible Promissory Note and Security Agreement                              
Line of credit                   $ 13.2          
Line of credit facility, expiration period                   12 months          
Line of credit, current                   $ 8.2          
Line of credit facility, current borrowing capacity                   $ 7.2          
2022 Secured Convertible Promissory Note and Security Agreement | Secured Debt                              
Line of credit facility, current borrowing capacity                         $ 7.5    
2022 Secured Convertible Promissory Note and Security Agreement | Secured Convertible Promissory Note                              
Line of credit facility, increase (decrease), net             $ 4.0   $ 2.0            
2022 Secured Note                              
Line of credit facility, increase (decrease), net $ 0.1 $ 0.5 $ 2.4   $ 4.4                    
Loan origination fee, percentage   4.00%                          
2022 Secured Note | Secured Debt                              
Line of credit                       $ 6.4 $ 20.2    
Merger Agreement                              
Other liabilities     $ 0.5                        
Merger Agreement | 2022 Warrants                              
Warrant, exercise price, increase (in usd per share) | $ / shares                       $ 25.01      
Warrant, exercise price, decrease (in usd per share) | $ / shares                       $ 20.75      
Registration Rights Agreements                              
Commitment fee percentage           7.00%                  
Juvenescence Limited                              
Gain (loss) on extinguishment of debt                     $ 36.0        
Juvenescence Limited | Secured Convertible Promissory Note                              
Line of credit facility, current borrowing capacity               $ 10.0              
Proceeds from issuance of long-term debt               10.0              
Juvenescence                              
Warrant purchase (in shares) | shares                         294,482 467,657  
Juvenescence | Secured Convertible Promissory Note                              
Convertiable promissoty note               $ 10.0              
Juvenescence | Merger Agreement                              
Warrant purchase (in shares) | shares                       129,593      
Stock issued during period shares issued cancelled (in shares) | shares                       164,889      
v3.25.1
Fair Value Measurements - Schedule of Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Warrant liability $ 3,582  
Convertible promissory notes   $ 2,983
Total 3,582 2,983
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Warrant liability 0  
Convertible promissory notes   0
Total 0 0
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Warrant liability 0  
Convertible promissory notes   0
Total 0 0
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Warrant liability 3,582  
Convertible promissory notes   2,983
Total $ 3,582 $ 2,983
v3.25.1
Fair Value Measurements - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
 6 Months Ended 12 Months Ended
Mar. 26, 2024
Mar. 15, 2023
Feb. 28, 2023
Dec. 31, 2024
Dec. 31, 2023
Jul. 26, 2023
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Change in fair value of convertible promissory notes       $ 7,017 $ (5,356)  
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]       Other income, net    
Change in fair value       $ (7,000) 7,000  
Assumed Warrants            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Exercise price of warrants or rights (in usd per share)       $ 20.47    
Warrant Liability            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Conversion of stock, shares issued (in shares) 0.97682654          
Common Stock            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Issuance of common stock upon conversion of AgeX-Serina Note (in shares)       2,501,000    
Convertible Promissory Note            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Debt instrument, face amount   $ 10,000        
Changes in fair value, gain (loss)   7,800        
Issued Interest Bearing Convertible Promissory Notes            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Debt instrument, face amount     $ 1,500      
Debt instrument, interest rate, stated percentage     6.00%      
Discount price     0.20      
Exercise price of warrants or rights (in usd per share)     $ 20.47      
Post-money valuation cap     $ 100,000      
Term of debt instrument     2 years      
Issued Interest Bearing Convertible Promissory Notes | Notes converted to Series A-5 pref. stock            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Conversion price (in usd per share)     $ 13.31      
Issued Interest Bearing Convertible Promissory Notes | Minimum            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Preferred stock for aggregate proceeds     $ 15,000      
Capitalization factor     $ 100,000      
Convertible Notes | Notes converted to Series A-5 pref. stock            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Shares issued upon conversion (in shares)           115,171
Change in fair value         $ 600  
Convertible Note Purchase Agreement | Juvenescence            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Debt instrument, face amount   $ 10,000        
Debt instrument, interest rate, stated percentage   7.00%        
v3.25.1
Fair Value Measurements - Schedule of Convertible Promissory Note Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Change in fair value $ 7,000 $ (7,000)
AgeX-Serina Note    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance 2,983 0
Conversion into equity (10,000)  
Change in fair value (7,017) (4,777)
Convertible debt issuance   10,000
Inception adjustment   (2,240)
Ending balance 0 2,983
AgeX-Serina Note | Notes converted to Series A-5 pref. stock    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Conversion into equity   0
AgeX-Serina Note | Notes converted to warrants    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Conversion into equity   0
Legacy Serina Convertible Notes    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance 0 1,617
Conversion into equity 0  
Change in fair value 0 (579)
Convertible debt issuance   100
Inception adjustment   0
Ending balance $ 0 0
Legacy Serina Convertible Notes | Notes converted to Series A-5 pref. stock    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Conversion into equity   (963)
Legacy Serina Convertible Notes | Notes converted to warrants    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Conversion into equity   $ (175)
v3.25.1
Fair Value Measurements - Schedule of Warrant Liability Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Class of Warrant or Right Outstanding [Roll Forward]    
Beginning balance $ 0  
Change in fair value 13,156 $ 1,077
Ending balance 3,582 0
Merger Warrants    
Class of Warrant or Right Outstanding [Roll Forward]    
Beginning balance 0  
Fair value at inception of Post-Merger Warrants 18,501  
Exercise (1,372)  
Derecognition of Incentive Warrants (1,798)  
Initial recognition of fair value of Replacement Incentive Warrants 1,407  
Change in fair value (13,156)  
Ending balance $ 3,582 $ 0
v3.25.1
Fair Value Measurements - Schedule of Estimates the Fair Value of Warrants (Details)
Dec. 31, 2024
Expected dividend yield  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Warrants and rights outstanding, measurement input 0.0000
Minimum  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Expected term (in years) 7 months 6 days
Minimum | Expected volatility  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Warrants and rights outstanding, measurement input 0.9915
Minimum | Risk-free interest rate  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Warrants and rights outstanding, measurement input 0.0414
Maximum  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Expected term (in years) 3 years 2 months 26 days
Maximum | Expected volatility  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Warrants and rights outstanding, measurement input 1.2589
Maximum | Risk-free interest rate  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]  
Warrants and rights outstanding, measurement input 0.0428
v3.25.1
Stockholders’ Equity/(Deficit) - Narrative (Details)
$ / shares in Units, $ in Thousands
 1 Months Ended 12 Months Ended
Jan. 31, 2025
shares
Nov. 27, 2024
USD ($)
shares
Nov. 26, 2024
USD ($)
tranche
$ / shares
shares
Mar. 14, 2024
Jan. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
$ / shares
shares
Sep. 30, 2024
shares
Jun. 06, 2024
USD ($)
$ / shares
shares
Mar. 31, 2024
$ / shares
shares
Mar. 26, 2024
$ / shares
Mar. 19, 2024
USD ($)
warrant
$ / shares
shares
Dec. 31, 2023
USD ($)
$ / shares
shares
Dec. 21, 2023
shares
Class of Stock [Line Items]                          
Common stock, voting rights           common stock are entitled to one vote for each share              
Common stock, shares authorized (in shares)           40,000,000     40,000,000     40,000,000  
Common stock, par or stated value per share (in usd per share) | $ / shares           $ 0.0001     $ 0.0001 $ 0.0001   $ 0.0001  
Preferred stock, shares authorized (in shares)                 5,000,000        
Preferred stock, par or stated value per share (in usd per share) | $ / shares                 $ 0.0001        
Class of warrant or right, number of securities called by each warrant or right (in shares)                     1    
Warrant purchase (in shares)                       53,980  
Warrant outstanding (in shares)           1,997,000           359,000  
Warrant liability | $           $ 3,582           $ 0  
Number Of Tranches | tranche     2                    
Issuance of stock | $           $ 36,404              
Stockholders' equity note, stock split, conversion ratio       0.02843332                  
Number of shares issued (in shares)     1,000,000                    
Common stock price per share (in dolalrs per share) | $ / shares     $ 10.00                    
Consideration for the purchase | $     $ 10,000                    
Share-Based Payment Arrangement, Tranche One                          
Class of Stock [Line Items]                          
Number of shares issued (in shares)   500,000                      
Consideration for the purchase | $   $ 5,000                      
Share-Based Payment Arrangement, Tranche One | Juvenescence                          
Class of Stock [Line Items]                          
Shares pledged (in shares)   122,136                      
Share-Based Payment Arrangement, Tranche Two | Subsequent Event                          
Class of Stock [Line Items]                          
Number of shares issued (in shares) 500,000                        
Consideration for the purchase | $         $ 5,000                
Post-Merger Warrants                          
Class of Stock [Line Items]                          
Number of warrants | warrant                     3    
Class of warrant or right, number of securities called by each warrant or right (in shares)                     5    
Class of warrant or right, exercise price of warrants or rights (in usd per share) | $ / shares               $ 13.20     $ 18.00    
Warrant purchase (in shares)     755,728     1   377,865     1,133,594    
Warrant outstanding (in shares)           366,691           0  
Warrant liability | $               $ 5,000          
Warrants issued (in shares)           1,500,000              
Warrant exchanged (in shares)           (755,000)              
Merger Warrants                          
Class of Stock [Line Items]                          
Other additional capital | $                     $ 15,000    
Warrant liability | $           $ 3,582           $ 0  
Derecognition of Incentive Warrants | $           1,798              
Initial recognition of fair value of Replacement Incentive Warrants | $           $ 1,407              
Incentive Warrants                          
Class of Stock [Line Items]                          
Number of warrants | warrant                     1    
Class of warrant or right, number of securities called by each warrant or right (in shares)                     1    
Class of warrant or right, exercise price of warrants or rights (in usd per share) | $ / shares           $ 18.00              
Warrant purchase (in shares)           377,865              
Warrant outstanding (in shares)           378,000           0  
Warrants and rights outstanding, maturity date           Mar. 26, 2028              
Warrants issued (in shares)           378,000              
Warrant exchanged (in shares)           0              
Replacement Incentive Warrants                          
Class of Stock [Line Items]                          
Warrant purchase (in shares)           755,728              
Warrant outstanding (in shares)                       0  
Warrants issued (in shares)           0              
Warrant exchanged (in shares)           756,000              
Assumed Warrants                          
Class of Stock [Line Items]                          
Class of warrant or right, exercise price of warrants or rights (in usd per share) | $ / shares           $ 20.47              
Warrant purchase (in shares)             473,681            
Warrant outstanding (in shares)             473,681            
Conversion of stock, shares issued (in shares)           0.97682654              
Notes converted to warrants                          
Class of Stock [Line Items]                          
Warrant purchase (in shares)           129,593              
Warrant outstanding (in shares)           129,593              
Warrants | Minimum                          
Class of Stock [Line Items]                          
Class of warrant or right, exercise price of warrants or rights (in usd per share) | $ / shares           $ 20.75              
Warrants | Maximum                          
Class of Stock [Line Items]                          
Class of warrant or right, exercise price of warrants or rights (in usd per share) | $ / shares           $ 25.01              
Redeemable convertible preferred stock                          
Class of Stock [Line Items]                          
Redeemable convertible preferred stock per share (in usd per share) | $ / shares                       $ 0.97682654  
Juvenescence                          
Class of Stock [Line Items]                          
Warrant purchase (in shares)                       294,482 467,657
Juvenescence | Replacement Incentive Warrants                          
Class of Stock [Line Items]                          
Warrant outstanding (in shares)           756,000              
v3.25.1
Stockholders’ Equity/(Deficit) - Schedule of Redeemable Convertible Preferred Stock (Details) - USD ($)
$ / shares in Units, shares in Thousands
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Class of Stock [Line Items]      
Shares Designated (in shares) 10 10  
Issue Price per Share (in usd per share) $ 0.01 $ 0.01  
Carrying Value $ 0 $ 36,404,000 $ 35,442,000
Liquidation Preference $ 0 $ 36,982,000  
Redeemable convertible preferred stock      
Class of Stock [Line Items]      
Redeemable convertible preferred stock per share (in usd per share)   $ 0.97682654  
Series A Preferred Stock      
Class of Stock [Line Items]      
Shares Designated (in shares)   391  
Shares Issued and Outstanding (in shares)   391  
Issue Price per Share (in usd per share)   $ 5.12  
Carrying Value   $ 2,000,000  
Liquidation Preference   $ 2,002,000  
Series A-1 Preferred Stock      
Class of Stock [Line Items]      
Shares Designated (in shares)   293  
Shares Issued and Outstanding (in shares)   293  
Issue Price per Share (in usd per share)   $ 6.82  
Carrying Value   $ 1,998,000  
Liquidation Preference   $ 1,998,000  
Series A-2 Preferred Stock      
Class of Stock [Line Items]      
Shares Designated (in shares)   1,091  
Shares Issued and Outstanding (in shares)   1,091  
Issue Price per Share (in usd per share)   $ 10.17  
Carrying Value   $ 11,085,000  
Liquidation Preference   $ 11,095,000  
Series A-3 Preferred Stock      
Class of Stock [Line Items]      
Shares Designated (in shares)   487  
Shares Issued and Outstanding (in shares)   487  
Issue Price per Share (in usd per share)   $ 12.80  
Carrying Value   $ 6,240,000  
Liquidation Preference   $ 6,234,000  
Series A-4 Preferred Stock      
Class of Stock [Line Items]      
Shares Designated (in shares)   702  
Shares Issued and Outstanding (in shares)   702  
Issue Price per Share (in usd per share)   $ 13.31  
Carrying Value   $ 9,347,000  
Liquidation Preference   $ 9,344,000  
Series A-5 Preferred Stock      
Class of Stock [Line Items]      
Shares Designated (in shares)   1,954  
Shares Issued and Outstanding (in shares)   474  
Issue Price per Share (in usd per share)   $ 13.31  
Carrying Value   $ 5,734,000  
Liquidation Preference   $ 6,309,000  
Redeemable Convertible Preferred Stock, Pre-Merger      
Class of Stock [Line Items]      
Shares Designated (in shares)   4,918  
Shares Issued and Outstanding (in shares)   3,438  
Carrying Value   $ 36,404,000  
v3.25.1
Stockholders’ Equity/(Deficit) - Reserved Common Stock on an As-Converted Basis for Future Issuance (Details) - shares
Dec. 31, 2024
Dec. 31, 2023
Equity [Abstract]    
Outstanding common stock warrants (in shares) 1,997,000 359,000
Outstanding common stock options under the Plans (in shares) 3,221,000 1,716,000
Reserved for future stock option grants (in shares) 1,977,000 13,000
Total common stock reserved for future issuance (in shares) 7,195,000 2,088,000
v3.25.1
Stockholders’ Equity/(Deficit) - Schedule of Warrant Activity (Details)
 12 Months Ended
Dec. 31, 2024
shares
Class of Warrant or Right [Line Items]  
Beginning balance (in shares) 359,000
Ending balance(in shares) 1,997,000
Post-Merger Warrants  
Class of Warrant or Right [Line Items]  
Beginning balance (in shares) 0
Warrants issued (in shares) 1,500,000
Warrants exercised (in shares) (378,000)
Ending balance(in shares) 366,691
Incentive Warrants  
Class of Warrant or Right [Line Items]  
Beginning balance (in shares) 0
Warrants issued (in shares) 378,000
Warrants exercised (in shares) 0
Ending balance(in shares) 378,000
Replacement Incentive Warrants  
Class of Warrant or Right [Line Items]  
Beginning balance (in shares) 0
Warrants issued (in shares) 0
Warrants exercised (in shares) 0
v3.25.1
Stock-Based Awards - Narrative (Details)
$ / shares in Units, $ in Thousands
 12 Months Ended
Mar. 14, 2024
Dec. 31, 2024
USD ($)
$ / shares
shares
Dec. 31, 2023
$ / shares
shares
Dec. 13, 2024
shares
Aug. 15, 2024
shares
Mar. 27, 2024
shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Number of shares available for grant (in shares)   1,977,000 13,000      
Options, outstanding, weighted average exercise price (in usd per share) | $ / shares   $ 4.81 $ 0.06      
Issuance of common stock upon exercise of stock options (in shares)   195,000        
Common stock, capital shares reserved for future issuance (in shares)   7,195,000 2,088,000      
Stockholders' equity note, stock split, conversion ratio 0.02843332          
Aggregate intrinsic value options exercisable | $   $ 7,530        
Weighted average remaining contractual term   7 years 8 months 12 days 7 years 6 months      
2024 Inducement Equity Plan            
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Number of shares available for grant (in shares)   955,000        
Award vesting period   10 years        
Shares available for grant, options granted (in shares)   45,000        
Options, outstanding, weighted average exercise price (in usd per share) | $ / shares   $ 5.30        
2024 Inducement Equity Plan | Restricted Stock Units (RSUs)            
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Number of shares available for grant (in shares)         1,000,000  
2024 Equity Incentive Plan            
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Number of shares available for grant (in shares)   1,022,208        
Award vesting period   10 years        
Shares available for grant, options granted (in shares)   1,652,792        
Issuance of common stock upon exercise of stock options (in shares)   0        
Grants in period, weighted average grant date fair value (in usd per share) | $ / shares   $ 7.83        
Cost not yet recognized, amount | $   $ 10,800        
Weighted average remaining contractual term   3 years 1 month 6 days        
2024 Equity Incentive Plan | Restricted Stock Units (RSUs)            
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Number of shares available for grant (in shares)           1,725,000
Common stock, capital shares reserved for future issuance (in shares)       950,000    
2024 Equity Incentive Plan | Minimum            
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Options, outstanding, weighted average exercise price (in usd per share) | $ / shares   $ 6.66        
2024 Equity Incentive Plan | Maximum            
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Options, outstanding, weighted average exercise price (in usd per share) | $ / shares   $ 14.87        
Serina 2017 Stock Option Plan            
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Shares available for grant, options granted (in shares)   1,521,172        
Options, outstanding, weighted average exercise price (in usd per share) | $ / shares   $ 0.06        
Issuance of common stock upon exercise of stock options (in shares)   194,932        
Conversion of stock, shares issued (in shares)   0.97682654        
Serina 2017 Equity Incentive Plan            
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Shares available for grant, options granted (in shares)   1,812        
Options, outstanding, weighted average exercise price (in usd per share) | $ / shares   $ 0.7751        
Issuance of common stock upon exercise of stock options (in shares)   0        
Common stock, capital shares reserved for future issuance (in shares)   241,683        
Stockholders' equity note, stock split, conversion ratio   0.02843332        
Serina 2017 Equity Incentive Plan | Minimum            
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]            
Options, outstanding, weighted average exercise price (in usd per share) | $ / shares   $ 13.19        
v3.25.1
Stock-Based Awards - Schedule of Stock Option Activity (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Number of Options Outstanding    
Beginning balance (in shares) 1,716,000  
Assumption of options in connection with the merger (in shares) 12,000  
Granted (in shares) 1,713,000  
Exercised (in shares) (195,000)  
Cancelled/Forfeited (in shares) (25,000)  
Ending balance (in shares) 3,221,000 1,716,000
Exercisable, number (in shares) 1,677,000  
Weighted- Average Exercise Price (per share)    
Beginning balance (in usd per share) $ 0.06  
Assumption of options in connection with the merger (in usd per share) 24.04  
Granted (in usd per share) 9.03  
Exercised (in usd per share) 0.06  
Cancelled/Forfeited (in usd per share) 13.59  
Ending balance (in usd per share) 4.81 $ 0.06
Exercisable, weighted average exercise price (in usd per share) $ 1.05  
Weighted-Average Remaining Contractual Term (in years)    
Weighted average remaining contractual term 7 years 8 months 12 days 7 years 6 months
Options exercisable December 31, 2024 6 years  
Beginning balance $ 0  
Exercised 1,753 $ 200
Ending balance 7,530 $ 0
Options exercisable December 31, 2024 $ 7,530  
v3.25.1
Stock-Based Awards - Schedule of Stock Based Compensation Expense (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Total stock-based compensation expense $ 2,595 $ 25
Research and development    
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Total stock-based compensation expense 551 0
General and administrative    
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Total stock-based compensation expense $ 2,044 $ 25
v3.25.1
Stock-Based Awards - Schedule of Weighted Average Assumptions to Calculate Fair Value of Stock Options (Details)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]    
Volatility   0.00%
Risk-free interest rates   0.00%
Dividend yield 0.00% 0.00%
Minimum    
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]    
Expected life (in years) 5 years  
Volatility 112.67%  
Risk-free interest rates 3.54%  
Maximum    
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]    
Expected life (in years) 6 years 1 month 6 days  
Volatility 118.33%  
Risk-free interest rates 4.65%  
v3.25.1
Profit Sharing Plan - Narrative (Details) - USD ($)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Postemployment Benefits [Abstract]    
Defined contribution plan, employer discretionary contribution amount $ 0 $ 0
v3.25.1
License Revenue (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 15, 2023
Dec. 31, 2024
Dec. 31, 2023
Oct. 31, 2023
Disaggregation of Revenue [Line Items]        
Total revenues   $ 56 $ 3,153  
License revenues        
Disaggregation of Revenue [Line Items]        
Total revenues $ 3,000 $ 0 $ 3,000  
License revenues | Minimum        
Disaggregation of Revenue [Line Items]        
Range of royalties on sales of products       2.75%
License revenues | Maximum        
Disaggregation of Revenue [Line Items]        
Range of royalties on sales of products       3.50%
v3.25.1
Income Taxes - Domestic And International Pre-Tax Income/(loss) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Income Tax Disclosure [Abstract]    
United States $ (11,141) $ 5,269
International 0 0
(Loss)/Income before income taxes $ (11,141) $ 5,269
v3.25.1
Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Deferred tax assets:    
Net operating loss $ 22,465 $ 10,170
Capital loss carryforward 6,922 8
Credits 2,446 2,050
Capitalized research costs 2,471 443
Stock based compensation - NQSO 558 0
Deferred lease liability 127 98
Accruals and reserves 221 0
Amortization and patent costs 453 0
Fixed assets 0 23
Other 8 190
Gross deferred tax assets 35,671 12,982
Valuation allowance (35,445) (12,842)
Deferred Tax Assets, Net of Valuation Allowance (226) (140)
Deferred tax liabilities:    
Fixed assets (76) 0
Lease ROU asset (150) (140)
Total deferred tax liabilities (226) (140)
Net deferred tax assets: $ 0 $ 0
v3.25.1
Income Taxes - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Income Tax Disclosure [Abstract]    
Total $ 0 $ 0
Effective Income Tax Rate Reconciliation [Line Items]    
Net change in the valuation allowance 22,600  
Operating loss carryforwards, not subject to expiration 63,100  
Unrecognized tax benefits 816 0
Unrecognized tax benefits, gross 100 100
Interest and penalties 0 $ 0
Domestic Tax Jurisdiction    
Effective Income Tax Rate Reconciliation [Line Items]    
Operating loss carryforwards, subject to expiration 87,800  
Domestic Tax Jurisdiction | Capital Loss Carryforward    
Effective Income Tax Rate Reconciliation [Line Items]    
Federal and state research credit carryforwards 25,000  
Domestic Tax Jurisdiction | Research Tax Credit Carryforward    
Effective Income Tax Rate Reconciliation [Line Items]    
Federal and state research credit carryforwards 2,900  
State and Local Jurisdiction    
Effective Income Tax Rate Reconciliation [Line Items]    
Operating loss carryforwards, subject to expiration 56,100  
State and Local Jurisdiction | Capital Loss Carryforward    
Effective Income Tax Rate Reconciliation [Line Items]    
Federal and state research credit carryforwards 18,700  
State and Local Jurisdiction | Research Tax Credit Carryforward    
Effective Income Tax Rate Reconciliation [Line Items]    
Federal and state research credit carryforwards $ 400  
v3.25.1
Income Taxes - Schedule of Income Tax Rate Reconciliation (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Income Tax Disclosure [Abstract]    
Federal tax at statutory rate $ (2,340) $ 1,107
State income taxes (724) (46)
Stock based compensation 0 5
Nondeductible items (4,327) (1,818)
Valuation allowance 22,603 752
Acquired NOLs (10,353) 0
Acquired capital loss (3,120) 0
Other items (1,739) 0
Total $ 0 $ 0
v3.25.1
Income Taxes - Schedule of Unrecognized Tax Benefits (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
USD ($)
Unrecognized Tax Benefits [Roll Forward]  
Balance at December 31, 2023 $ 0
Increase in balance upon Merger 264
Increase in balance related to tax positions taken during prior years 552
Balance at December 31, 2024 $ 816
v3.25.1
Commitments and Contingencies - Narrative (Details)
$ in Thousands
 1 Months Ended 12 Months Ended
May 31, 2024
USD ($)
Dec. 31, 2024
numberOfFinanceLeases
Other Commitments [Line Items]    
Lease renewal period   2 years
Leased pieces of equipment   2
Expired leases   1
Enable Arrangement    
Other Commitments [Line Items]    
Payments to acquire intangible assets | $ $ 2,000  
v3.25.1
Commitments and Contingencies - Schedule of Cash Flow Information Related to Leases (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Cash paid for amounts included in the measurement of lease liabilities:    
Operating cash flows from operating leases $ 214 $ 188
Operating cash flows from finance leases 2 7
Financing cash flows from finance leases 35 48
Right-of-use assets obtained in exchange for lease obligations    
Operating leases 0 755
Finance leases $ 0 $ 0
v3.25.1
Commitments and Contingencies - Schedule of Supplemental Balance Sheet Information Related to Leases (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Operating lease    
Right-of-use assets $ 862 $ 862
Accumulated amortization (401) (196)
Right-of-use asset, net $ 461 $ 666
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other current liabilities Other current liabilities
Right-of-use lease liability, current $ 192 $ 214
Right-of-use lease liability, noncurrent 268 461
Total operating lease liabilities 460 675
Finance leases    
Right-of-use assets 163 163
Accumulated amortization (77) (53)
Right-of-use asset, net $ 86 $ 110
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other current liabilities Other current liabilities
Right-of-use lease liability, current $ 1 $ 36
Right-of-use lease liability, noncurrent 0 1
Total finance lease liabilities $ 1 $ 37
Weighted average remaining lease term    
Operating lease 2 years 6 months 10 days 3 years 3 months 25 days
Finance leases 1 month 28 days 7 months 20 days
Weighted average discount rate    
Operating lease 6.67% 6.67%
Finance leases 6.67% 11.90%
v3.25.1
Commitments and Contingencies - Schedule of Annual Undiscounted Cash Flows of The Lease Liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2024
Dec. 31, 2023
Operating Leases    
Year ending December 31, 2025 $ 217  
Year ending December 31, 2026 159  
Year ending December 31, 2027 117  
Year ending December 31, 2028 10  
Total undiscounted lease payments 503  
Less: imputed interest (43)  
Total lease obligations 460 $ 675
Less: current portion (192) (214)
Operating lease liabilities, net of current portion $ 268 $ 461
v3.25.1
Net Earnings (Loss) Per Common Share - Schedule of Basic and Diluted Net Earnings (Loss) Per Common Share Attributable to Common Shareholders (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
NUMERATOR    
Net (loss) income $ (11,207) $ 5,269
Less: net loss attributable to noncontrolling interest 66 0
Net (loss) earnings attributable to Serina $ (11,141) $ 5,269
DENOMINATOR    
Weighted-average shares of common stock outstanding used to calculate basic net (loss) earnings per common share (in shares) 7,359 2,235
Basic net (loss) earnings per common share allocable to common stockholders (in usd per share) $ (1.51) $ 2.36
NUMERATOR    
Net (loss) earnings attributable to Serina $ (11,141) $ 5,269
Add back: interest on convertible promissory notes 0 83
Net (loss) earnings allocable to common stockholders $ (11,141) $ 5,352
DENOMINATOR    
Weighted-average shares of common stock outstanding used to calculate basic net (loss) earnings per common share (in shares) 7,359 2,235
Add: dilutive effect of stock options 0 1,677
Add: dilutive effect of common stock issued for convertible promissory notes 0 0
Add: dilutive effect of redeemable convertible preferred stock 0 3,439
Weighted-average shares of common stock outstanding used to calculate diluted net (loss) earnings per common share (in shares) 7,359 7,351
Diluted net (loss) earnings per common share attributable to common stockholders (in usd per share) $ (1.51) $ 0.73
v3.25.1
Net Earnings (Loss) Per Common Share - Schedule of Diluted Net Earnings (loss) Per Common Share (Details) - shares
shares in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Antidilutive securities ( in shares) 5,218 474
Stock options    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Antidilutive securities ( in shares) 3,221 0
Warrants    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Antidilutive securities ( in shares) 1,997 474
v3.25.1
Segment Reporting (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
USD ($)
segment
Dec. 31, 2023
USD ($)
Segment Reporting [Abstract]    
Number of reportable segments | segment 1  
Revenue, Major Customer [Line Items]    
Total revenues $ 56 $ 3,153
Research and development 7,480 2,388
General and administrative 9,624 3,894
Total operating expenses 17,104 6,282
Loss from operations (17,048) (3,129)
Interest expense (526) (558)
Total other income, net 5,841 8,398
Reportable Segment    
Revenue, Major Customer [Line Items]    
Total revenues 56 3,153
Depreciation 218 131
Total operating expenses 17,104 6,282
Loss from operations (17,048) (3,129)
Interest expense (526) (558)
Interest income 235 283
Other income, net 6,132 8,673
Total other income, net (11,207) 5,269
Reportable Segment | Project specific    
Revenue, Major Customer [Line Items]    
Research and development 2,962 698
Reportable Segment | Non-Project specific    
Revenue, Major Customer [Line Items]    
Research and development 475 320
Reportable Segment | Compensation    
Revenue, Major Customer [Line Items]    
Research and development 3,462 1,212
General and administrative 4,468 1,213
Reportable Segment | Infrastructure Management and Facilities    
Revenue, Major Customer [Line Items]    
Research and development 363 27
General and administrative 339 236
Reportable Segment | Professional and outside service fees    
Revenue, Major Customer [Line Items]    
General and administrative 3,341 846
Reportable Segment | Merger and Integration related    
Revenue, Major Customer [Line Items]    
General and administrative $ 1,476 $ 1,599