NewLimit

NewLimit is an American biotechnology company, headquartered in South San Francisco, California, that is developing medicines intended to restore youthful function to old cells through epigenetic reprogramming.^[1][2] It was announced in December 2021 by Brian Armstrong, the co-founder and CEO of Coinbase, and Blake Byers, a former general partner at GV. Jacob Kimmel, a stem cell biologist who had led a reprogramming research group at Calico, joined as a co-founder in 2022 and is the company's CEO and president.^[3][4][2] NewLimit searches for combinations of transcription factors, which it calls "payloads", that make aged human cells look and act younger. It tests thousands of combinations at once in pooled single-cell screens and uses an in-house machine learning system called Ambrosia to choose which combinations to test next.^[5][6]

As of October 2026 the company has no product in human trials.^[7] Its first candidate medicine is a lipid nanoparticle (LNP) carrying messenger RNA that encodes fewer than ten transcription factors, aimed at hepatocytes in the liver. NewLimit has said it plans to begin its first human trial in 2027, starting with patients who have fatty liver disease.^[8][9] In June 2026 it closed a $435 million Series C led by Founders Fund, and Kimmel told STAT that the company was valued at around $3.1 billion.^[1][2] Endpoints News put the company's total funding at $682 million in September 2026.^[10]

Overview

History

Founding (2021-2022)

Armstrong and Byers announced NewLimit on December 11, 2021, describing a company "with the mission of extending human healthspan."^[3] The launch post said the company would start by studying epigenetic drivers of aging, using primary human cells and reference species to build machine learning models of which chromatin features change with age and which of those changes might cause aging, and would then try to develop therapies that "could slow, halt, or reverse this process."^[3] It pointed to the induced pluripotent stem cell work of Shinya Yamanaka and colleagues, in which a handful of transcription factors turn adult cells back into embryonic-like stem cells, as the reason for focusing on epigenetic reprogramming.^[3] The founders compared the culture they wanted to that of SpaceX and said their goal was "an ambitious, well run, for-profit company" rather than an academic institute.^[3]

The launch post said the founders had initially put $105 million into the company.^[3] In 2023 the company described the founders' original commitment as $110 million, and Fortune reported that Armstrong had sold 2% of his holdings in Coinbase to invest an initial $110 million in the venture alongside Byers.^[12][13] Fortune also described Armstrong and Byers as two of NewLimit's four co-founders; the company's current leadership page lists Armstrong, Byers and Kimmel as co-founders.^[13][4]

NewLimit named its first scientific advisers, UCSF immunologist Alex Marson and Stanford immunologist Mark M. Davis, in January 2022.^[14] Kimmel left Calico, the Google-funded aging research lab, in 2022 to co-found NewLimit.^[15] By August 2022 the team was moving equipment into its South San Francisco office and preparing to run its first experiments by the end of that month.^[16] The company was announced in 2021 and began laboratory work in 2022; sources give either year as its founding date, and NewLimit's own posts use both.^[2][6][16]

Building the discovery platform (2023-2024)

In May 2023 NewLimit announced a $40 million Series A from Dimension, Founders Fund and Kleiner Perkins, with participation from Eric Schmidt, Elad Gil, Garry Tan and Fred Ehrsam.^[12] The company said it was looking for "sets of transcription factors that can epigenetically reprogram cells", and that although its products were designed to treat aging itself, they might also treat diseases associated with aging such as fibrosis, infectious disease and neurodegenerative disease.^[12] Armstrong told Fortune that the company's focus was "health span" rather than life span, and NewLimit declined to give a timeline for commercializing its research.^[13]

In its review of 2023, the company's first full calendar year of operations, NewLimit reported that its team had grown from 12 to 24 people. It had built gene delivery tools that could put combinations of reprogramming factors into primary human cells, and a sequencing method it called pxbc-seq for reading the "perturbation barcodes" that record which factors each cell received.^[17] In 2024 it reported finding transcription factor sets that restored youthful gene expression in T cells and hepatocytes without abolishing their cell type programs. It ran its first in vivo screens on human hepatocytes in a humanized liver late that year, and when one of the resulting transcription factor sets was delivered as an LNP-mRNA formulation to old mice with liver injury, it restored the regenerative capacity that had been lost with age.^[18]

Series B, first candidate and clinical plans (2025-2026)

In May 2025 NewLimit raised a $130 million Series B led by Kleiner Perkins. New investors were Nat Friedman and Daniel Gross, Khosla Ventures, Human Capital and Valor Equity Partners, joined by existing investors Dimension, Founders Fund and Armstrong.^[19] Axios reported that the round valued the company at $810 million.^[20] Kimmel, then the company's president, told Fierce Biotech that the first target would be alcohol-related liver disease and that NewLimit was developing intravenous medicines meant to be dosed every three weeks at the shortest interval.^[21] Quartz, citing The Wall Street Journal, later reported that executives had said at the time of the Series B that the first human trial might not happen until as late as 2030.^[22]

The company launched a third therapeutic program, focused on the endothelial cells that line blood vessels, in August 2025, and added kidney researchers Matthew Breyer and Benjamin Humphreys to its scientific advisory board to support it.^[6][23] In September 2025 it selected a lead hepatocyte payload for development and began a lead optimization campaign on the mRNA sequence, which it said raised potency 1.6-fold and specificity for hepatocytes 8-fold.^[24] In October 2025 it announced a further $45 million from Eli Lilly and Company, Duke Management Co, Section 32 and others "on a $1.62B cap", with existing investors including Kleiner Perkins, Dimension, Abstract, Human Capital and Boost also taking part.^[25]

By the end of 2025 NewLimit had declared its first preclinical candidate. The company said the payload restored both regenerative capacity after surgical liver injury and resilience to alcohol-induced damage in old animals, and that neither liver toxicity nor neoplasia was seen at doses far above the therapeutic level.^[6] It said it had reached this stage after about three years of operations, compared with the five or more years it had expected when it was founded.^[6]

On June 2, 2026, NewLimit announced a $435 million Series C led by Founders Fund, with new investors Thrive Capital, Greenoaks and Quiet Capital and returning investors including Kleiner Perkins, Abstract, Nat Friedman and Daniel Gross, Valor Equity Partners, Eli Lilly Ventures and Human Capital.^[2][26] Kimmel told STAT the company was valued at around $3.1 billion, and Endpoints News reported a $3.1 billion post-money valuation.^[1][9] The company said its first medicine would enter human trials "next year", and attributed the faster timeline to "the breakthrough discovery of a prototype medicine that reverses cell age in old human liver cells."^[2] According to Fierce Biotech, the phase 1 trial will focus on patients with fatty livers from a range of causes, phase 2 development will then narrow to alcohol-related liver disease, and the medicine is initially planned as a monthly intravenous infusion. Fierce reported that the company had about 50 employees.^[8]

Later in 2026 NewLimit hired Melissa Calton, previously a vice president of early-stage product development at 4D Molecular Therapeutics, as head of translation, and Hank Mansbach, previously chief medical officer of 89bio, as head of clinical development.^[27][7] In September 2026 Endpoints News named NewLimit a winner of its 2026 Endpoints 11.^[10] In its October 2026 update, the company reported that it had scaled manufacturing of its LNP-RNA product more than 314-fold since the start of the year, run its first large-animal studies, and had "productive engagements with regulators" ahead of a trial it still planned to start in 2027.^[7]

Science and technology

Partial reprogramming

Every cell in the body carries the same DNA, and epigenetic marks on DNA and its associated proteins determine which genes each cell uses. NewLimit's premise is that these marks degrade with age, and that they can be rewritten by activating combinations of transcription factor genes.^[5] The idea builds on Yamanaka's finding that four transcription factors can return adult cells to a pluripotent state, and on later experiments showing that brief, or "partial", activation of reprogramming factors can reverse molecular and functional features of aging.^[3][28] Full reprogramming erases a cell's adult identity, and NewLimit has said that the Yamanaka factors suppress adult cell type programs, which raises the risk of neoplasia and limits their use as medicines. Its stated goal is to find payloads that reverse cell age while preserving cell type.^[18][28]

Kimmel worked on this question before NewLimit. A 2022 Cell Systems paper from his Calico group, with Kimmel as senior author, used single-cell genomics to follow partial reprogramming in several mouse cell types and screened every subset of the Yamanaka factors in pooled single-cell screens. It found that partial reprogramming restored youthful gene expression but temporarily suppressed somatic identity programs, and that these two effects "were not tightly entangled."^[29] His earlier Calico papers include a single-cell RNA-seq study of aging in more than 50,000 cells from three tissues in young and old mice, and scNym, a semi-supervised adversarial neural network that transfers cell-type labels between single-cell experiments.^[30][31]

Discovery Engine

NewLimit calls its platform the Discovery Engine and describes it as a three-step loop.^[5]

The company has also built a humanized liver screening system that measures the effect of pooled payloads on old human hepatocytes inside an injured liver, so that large hepatocyte screens can be run in vivo.^[6] National Geographic photographed the system and described it as human liver tissue developed in genetically engineered mice.^[15] NewLimit has claimed that, to its knowledge, it had tested more than 1,000 times as many reprogramming payloads by the end of 2025 as the rest of the field combined.^[6] In March 2026 it reported a "biological scaling law": the quality of its best payloads improved log-linearly with the number of hits it had observed.^[32]

Ambrosia

Ambrosia was described in "In silico design of epigenetic reprogramming payloads", a poster at the 2nd Generative AI for Biology Workshop at ICML 2025 by Lucas Seninge, Conner Kummerlowe, David Reynolds, Nicholas Bernstein and Kimmel.^[33] The paper notes that even payloads of fewer than six transcription factors, drawn from the roughly 2,000 encoded in the human genome, give about 10^16 possible combinations, far more than can be tested in a laboratory.^[34]

In the paper's design, each transcription factor is represented by an embedding from a pre-trained protein language model (the paper cites the 2023 ESM-2 paper by Lin and colleagues, which also introduced ESMFold), and the embeddings in a payload are summed into a single set representation, an approach the authors say was inspired by deep sets. A small neural network with Monte Carlo dropout then predicts the payload's effect on cell state along with an uncertainty estimate, and the trained model is used to propose new payloads, including through a generative MCMC sampling procedure.^[34] The models were trained on a public combinatorial CRISPR interference dataset in K562 cells and on a proprietary NewLimit dataset covering 6,503 transcription factor sets (580 unique factors) across 3.6 million primary human T cells with single-cell RNA-seq readouts.^[34] The authors reported that Ambrosia beat baseline methods, including an additive model, on cell state and function prediction, that its performance followed a data scaling law, and that in a simulated lab-in-the-loop it found successful payloads faster than experimental search alone.^[33][34]

NewLimit describes the prediction task as a special case of perturbation prediction, or "virtual cell" modeling.^[6] The company has since reported several upgrades in its blog. A multi-task version introduced in January 2026 predicts several effects at once, such as reversing cell age while preserving cell type, and the company said it more than doubled the number of hits found per dollar compared with a baseline.^[32] In mid-2026 it reported early transfer learning across cell types, with a generalized model matching a lineage-specific one on endothelial cells using about a third of the endothelial data; by October 2026 it said adding hepatocyte and T cell data had improved data efficiency for endothelial function prediction more than five-fold.^[27][7] These later results were reported on the company's blog rather than in a paper.

Therapeutic programs

NewLimit's medicines are LNPs carrying RNA that activates a payload of transcription factors in a target cell type.^[8][7] The company has three programs.^[11]

In the liver program, the company reported that old mice given its candidate tolerated alcohol more like young mice, which Kimmel said was visible "with your naked eye", and that resilience to dietary damage persisted after the medicine had cleared from the body.^[8][27] Kimmel declined to tell Fierce Biotech which transcription factors make up the lead payload.^[8]

Funding

The company's Series B announcement also listed angel investors John and Patrick Collison, Fred Ehrsam, Elad Gil, Joshua Kushner, Joe Lonsdale and Garry Tan.^[19] Its website also lists Liberty Mutual Investments among its investors.^[4]

Leadership and advisers

The company's biography of Byers says he was the first investor in Robinhood, IonQ and Arcus while at GV, and lists his current investments as including OpenAI, Anthropic, xAI, Neuralink and Chai Discovery.^[4]

NewLimit's scientific advisory board consists of Alex Marson (UCSF and the Gladstone-UCSF Institute of Genomic Immunology), Mark M. Davis (Stanford), E. John Wherry (University of Pennsylvania), Hao Zhu (UT Southwestern), Markus Grompe (Oregon Health and Science University), Matthew Breyer (Janssen) and Benjamin Humphreys (Washington University in St. Louis).^[4]

Reception and context

Quartz described longevity as a favored destination for wealth from the technology industry, and both Quartz and National Geographic placed NewLimit alongside Altos Labs, which launched in 2022 with $3 billion, and Retro Biosciences, which received $180 million from OpenAI CEO Sam Altman.^[22][15] Quartz, citing The Wall Street Journal, reported that NewLimit's $3.1 billion valuation topped the $1.8 billion figure Retro Biosciences had reported the previous month.^[22] National Geographic's August 2026 feature on cellular reprogramming noted NewLimit's plan to start human trials and cautioned, about the field's early therapies in general: "It is possible that nothing will come of these initial efforts, at least not in their current form or not for a long time."^[15]

Kimmel has positioned the company against the field's reputation for hype. "Historically, there has been a lot of over-salesmanship and a lack of real rigorous science in aging biology," he told Fierce Biotech in June 2026.^[8] The company posts detailed progress updates on its blog, most of them covering two-month periods, and holds a yearly presentation of its progress for invited scientists and engineers.^[32][27][35]

Debarghya Das's "The Ultimate Neolab List" includes NewLimit but marks it "Not a neolab", describing it as a "preclinical wet-lab drug developer heading to trials, not a software/model company."^[36]

See also

• List of neolabs
• Neolab
• AI in drug discovery
• State (Arc Institute virtual cell model)
• Single-cell RNA sequencing
• Chai Discovery

References

1. ^1 ^2 ^3 ^4 ^5Allison DeAngelis, STAT. "Longevity startup NewLimit raises $435 million ahead of first clinical trial". June 2, 2026.
2. ^1 ^2 ^3 ^4 ^5 ^6 ^7 ^8 ^9 ^10 ^11 ^12Jacob C. Kimmel, NewLimit Blog. "NewLimit raises $435M led by Founders Fund to bring longevity medicines to human trials". June 2, 2026.
3. ^1 ^2 ^3 ^4 ^5 ^6 ^7 ^8 ^9 ^10Brian Armstrong and Blake Byers, NewLimit Blog. "Announcing NewLimit: a company built to extend human healthspan". December 11, 2021.
4. ^1 ^2 ^3 ^4 ^5 ^6 ^7 ^8 ^9 ^10 ^11 ^12 ^13NewLimit. "Company". Company website, accessed October 27, 2026.
5. ^1 ^2 ^3 ^4 ^5 ^6 ^7NewLimit. "Science". Company website, accessed October 27, 2026.
6. ^1 ^2 ^3 ^4 ^5 ^6 ^7 ^8 ^9 ^10Jacob C. Kimmel, NewLimit Blog. "2025 Year in Review". January 6, 2026.
7. ^1 ^2 ^3 ^4 ^5 ^6 ^7Jacob C. Kimmel, NewLimit Blog. "2026 Summer". October 21, 2026.
8. ^1 ^2 ^3 ^4 ^5 ^6 ^7 ^8 ^9 ^10Darren Incorvaia, Fierce Biotech. "New heights for NewLimit as anti-aging biotech nabs $435M to rejuvenate old cells". June 2, 2026.
9. ^1 ^2 ^3 ^4Andrew Dunn, Endpoints News. "Anti-aging startup NewLimit raises $435M at $3B+ valuation, eyes clinic in 2027". June 2, 2026.
10. ^1 ^2 ^3Andrew Dunn, Endpoints News. "Endpoints 11: NewLimit searches far beyond Yamanaka for a new class of anti-aging medicines". September 25, 2026.
11. ^1 ^2 ^3 ^4NewLimit. "Therapeutics". Company website, accessed October 27, 2026.
12. ^1 ^2 ^3 ^4 ^5 ^6Brian Armstrong, Blake Byers, Greg Johnson and Jacob C. Kimmel, NewLimit Blog. "NewLimit secures $40 million in venture funding from Dimension Capital, Founders Fund, Kleiner Perkins and other investors". May 16, 2023.
13. ^1 ^2 ^3Jeff John Roberts, Fortune. "Coinbase founder Brian Armstrong raises $40 million for NewLimit, a startup that wants to 'cure aging'". May 16, 2023.
14. ^Brian Armstrong, NewLimit Blog. "We've added two members to our Scientific Advisory Board: Alex Marson and Mark M. Davis". January 8, 2022.
15. ^1 ^2 ^3 ^4D. T. Max, National Geographic. "Are We on the Brink of Ending Aging?". August 6, 2026.
16. ^1 ^2Brian Armstrong, NewLimit Blog. "July 2022 Progress Update". August 10, 2022.
17. ^Jacob C. Kimmel, NewLimit Blog. "2023 Year in Review". January 9, 2024.
18. ^1 ^2Jacob C. Kimmel, NewLimit Blog. "2024 Year in Review". January 9, 2025.
19. ^1 ^2 ^3 ^4Brian Armstrong, Blake Byers, Cathy O'Hare and Jacob C. Kimmel, NewLimit Blog. "NewLimit raises $130 million Series B led by Kleiner Perkins alongside NFDG, Khosla Ventures, Human Capital and others". May 6, 2025.
20. ^1 ^2Lucinda Shen, Axios Pro. "First Look: Axios Pro Premium". May 6, 2025.
21. ^Darren Incorvaia, Fierce Biotech. "Anti-aging biotech NewLimit raises $130M to push liver reprogramming med into clinic". May 6, 2025.
22. ^1 ^2 ^3Colleen Cabili, Quartz. "Coinbase CEO's anti-aging startup NewLimit is raising $435 million, tripling its valuation". June 3, 2026.
23. ^1 ^2Jacob C. Kimmel, NewLimit Blog. "July // August 2025 Progress Update". September 30, 2025.
24. ^Jacob C. Kimmel, NewLimit Blog. "September // October 2025 Progress Update". November 24, 2025.
25. ^1 ^2 ^3 ^4Jacob C. Kimmel, Brian Armstrong, Blake Byers and Cathy O'Hare, NewLimit Blog. "NewLimit has raised an additional $45M from Lilly, Duke University, Section 32, & Abstract on a $1.62B cap". October 20, 2025.
26. ^Latham & Watkins. "Latham & Watkins Advises NewLimit on US$435 Million Series C". June 4, 2026.
27. ^1 ^2 ^3 ^4 ^5Jacob C. Kimmel, NewLimit Blog. "2026 May // June Progress Update". July 10, 2026.
28. ^1 ^2Jacob C. Kimmel, NewLimit Blog. "Developing reprogramming therapies". August 11, 2022.
29. ^Antoine E. Roux, Chunlian Zhang, Jonathan Paw, Jose Zavala-Solorio, Evangelia Malahias, Twaritha Vijay, Ganesh Kolumam, Cynthia Kenyon and Jacob C. Kimmel. "Diverse partial reprogramming strategies restore youthful gene expression and transiently suppress cell identity". Cell Systems 13(7), 2022.
30. ^Jacob C. Kimmel, Lolita Penland, Nimrod D. Rubinstein, David G. Hendrickson, David R. Kelley and Adam Z. Rosenthal. "Murine single-cell RNA-seq reveals cell-identity- and tissue-specific trajectories of aging". Genome Research 29(12), 2019.
31. ^Jacob C. Kimmel and David R. Kelley. "Semisupervised adversarial neural networks for single-cell classification". Genome Research 31(10), 2021.
32. ^1 ^2 ^3Jacob C. Kimmel, NewLimit Blog. "January // February 2026 Progress Update". March 27, 2026.
33. ^1 ^2Lucas Seninge, Conner Kummerlowe, David Reynolds, Nicholas Bernstein and Jacob Kimmel. "In silico design of epigenetic reprogramming payloads". 2nd Generative AI for Biology Workshop, ICML 2025.
34. ^1 ^2 ^3 ^4NewLimit. "In silico design of epigenetic reprogramming payloads" (project page). 2025.
35. ^Jacob C. Kimmel, NewLimit Blog. "2026 Progress Update". June 9, 2026.
36. ^Debarghya Das. "The Ultimate Neolab List". Accessed October 27, 2026.