Not investment advice. Not medical advice. Full disclosure at the bottom.
Altos Labs launched with approximately $3 billion in 2022. Jeff Bezos reportedly backed it. Shinya Yamanaka, the Nobel Prize winner who discovered the reprogramming factors this entire field is built on, joined as an advisor. The message was unmistakable: the serious money has decided that reversing cellular age is a real science worth betting on at scale.
The problem is that Altos is private. You cannot buy it. And the same is true of almost every compelling company building on this science right now.
That is not a reason to stop paying attention. It is a reason to build the watchlist now, understand the science before the institutional narrative catches up, and know exactly what to look for when these names eventually seek liquidity. I also want to be straight with you about the one name that is actually publicly accessible today, because it exists and it deserves an honest read, not a promotional one.
That is what this article is. A watchlist with honest flags on every entry, for a category I believe is one of the most important in longevity biotech and one of the most early in its transition from lab to clinic.
The Science In Plain English
Your DNA does not change much as you age. What changes is the layer of chemical instructions sitting on top of your DNA that tells your genes which ones to turn on and which ones to stay off. That layer is called the epigenome. As it degrades over decades, cells start behaving like confused, tired versions of themselves. They lose their specialized function. They accumulate errors. They contribute to the full range of age-related disease.
In 2006, Shinya Yamanaka discovered that four transcription factors, proteins your cells make that control gene activity, could reset an adult cell all the way back to an embryonic stem cell state. The problem with full reprogramming is that it also erases cell identity. A heart cell that forgets it is a heart cell is not useful. Worse, fully reprogrammed cells can become tumors.
Partial reprogramming solves that. David Sinclair's lab at Harvard showed in a 2020 paper published in Nature that using three of the four Yamanaka factors, specifically OSK (Oct4, Sox2, Klf4) without c-Myc, could reset the epigenetic age of cells without erasing their identity. The cells remembered what they were. They just behaved younger. In mice with optic nerve damage, vision-related outcomes improved. That paper helped catalyze the current wave of clinical interest. Partial reprogramming is now the leading approach in cellular rejuvenation: enough reset to reverse functional decline, not so much that the cell loses itself or becomes dangerous.
Why 2026 Is the Year To Pay Attention
In January 2026, the FDA cleared the first ever investigational new drug application for a partial epigenetic reprogramming therapy. Life Biosciences received IND clearance for ER-100, their OSK gene therapy for optic neuropathies including glaucoma. Life Biosciences describes this as the first epigenetic-reprogramming-based cellular rejuvenation therapy cleared to enter human trials. First human dosing is expected in 2026.
Safety signals from ER-100 will tell every other company in this space whether the basic mechanism holds in humans and whether the controlled-expression approach that avoids full reprogramming is as safe as the preclinical data suggested. YouthBio Therapeutics completed a productive INTERACT meeting with the FDA in September 2025 for their Alzheimer's partial reprogramming gene therapy YB002, with the FDA endorsing a path toward first-in-human testing. NewLimit, backed by Eli Lilly, Kleiner Perkins, and Founders Fund at a reported valuation of approximately $1.62 billion as of October 2025, says it is in IND-enabling studies for its lead liver program. Multiple data readouts and regulatory interactions are landing in 2026 that will begin to answer whether this science translates from animal models to humans.
Before I get to the five companies, I want to flag that the full 25-Gate scores for all of them are in the Founder's Research Bundle, including which one I think has the cleanest safety profile and why. If you want that detail alongside the names, the bundle is where it lives. [https://everlifecapital.com/research-bundle/]
The Watchlist
A transparency note before we start. Four of the five companies below are private. That is the honest state of the category in early 2026. The most scientifically credible partial reprogramming programs have not yet sought public market liquidity. The fifth is a publicly listed name, and I cover it last with a full honest read including the risks. I am publishing this list now because the time to understand a category is before the IPO window opens, not after.
1. Life Biosciences (private, Boston)
What they are doing differently. They are first to human trials with a partial reprogramming therapy. ER-100 uses OSK delivered via a doxycycline-inducible system, meaning gene expression can be paused or stopped if needed. Local delivery to the eye limits systemic exposure. Their liver program ER-300 showed improved liver function scores in a mouse model of liver disease at the ARDD meeting in August 2025. Co-founded by David Sinclair, whose 2020 Nature paper is the scientific foundation for the OSK approach.
L-45 filter. Glaucoma risk rises with age and accelerates after 50. More importantly, if the safety profile holds in the eye, the platform case for applying OSK to the liver, heart, and brain becomes substantially more credible. A 45-year-old watching this trial is watching the first human test of a mechanism that could eventually apply to every organ system.
Gate highlights. Gate 1 (Leadership) scores high: CEO Jerry McLaughlin brings pharma commercialization experience from Merck and venture-backed biotechs. Gate 7b (Endpoint Risk) scores well because the eye is a contained, measurable system with clear functional endpoints. The doxycycline kill-switch is the best Gate 21 answer in this space.
One thing to watch. First patient safety data from ER-100. Any tumor-related adverse event would reset the entire field's risk calculus. A clean six-month safety readout would be the most important data point in longevity biotech in years.
2. NewLimit (private, South San Francisco)
What they are doing differently. Rather than using Yamanaka factors directly, NewLimit is searching for entirely new combinations of transcription factors that produce youthful cellular phenotypes. The company reports testing more than 3,000 transcription factor combinations and identifying more than 20 sets that restore youthful phenotypes in aged liver cells. They are also running immune cell rejuvenation and vascular programs in parallel. Co-founded by Coinbase CEO Brian Armstrong. Eli Lilly invested directly alongside Kleiner Perkins and Founders Fund in an October 2025 round that reportedly valued the company at approximately $1.62 billion.
L-45 filter. Liver function declines measurably in the 40s. Immune cell senescence, the progressive degradation of T cell killing activity, begins well before clinical symptoms appear. NewLimit's three-program structure across liver, immune, and vascular systems maps directly onto where silent functional decline begins in otherwise healthy people in their mid-40s.
Gate highlights. Gate 5 (Market Size) scores very high: their multi-system platform approach, if validated, addresses virtually every major age-related disease category. Eli Lilly's direct investment is among the strongest institutional confidence signals in the field. Gate 2 (Clinical Data) is preclinical only, which limits the composite score until IND-enabling studies produce safety data.
One thing to watch. The IND filing timeline for the liver program. Any announcement of a pre-IND meeting with FDA is the trigger for a full 25-Gate re-evaluation.
3. YouthBio Therapeutics (private, Seattle)
What they are doing differently. YouthBio is taking partial reprogramming to the brain first, specifically Alzheimer's disease, with their candidate YB002. Most companies in this space have avoided CNS as a first indication because of delivery complexity. CEO Yuri Deigin has argued publicly that neurons are more resistant to de-differentiation than other cell types, providing a wider safety window for the approach. The FDA's September 2025 INTERACT response endorsed their preclinical data and supported a path toward first-in-human testing.
L-45 filter. Alzheimer's pathology begins accumulating decades before clinical symptoms. Amyloid and tau changes are measurable in people in their 40s who will not develop symptoms until their 60s or 70s. A therapy that addresses upstream epigenetic drivers of neurodegeneration is directly relevant to the prevention window, not just the treatment window.
Gate highlights. Gate 9 (Governance) scores cleanly: capital-efficient strategy, no dilution red flags, founder-led with a clear development path. Gate 7b (Endpoint Risk) needs more work: Alzheimer's trials have a long history of mechanistically compelling drugs that failed to convert to clinical benefit.
One thing to watch. The pre-IND meeting outcome. YouthBio guided approximately 18 months of CMC and pilot toxicology work following the INTERACT meeting. Progress updates on that timeline tell the story on execution risk.
4. Shift Bioscience (private, Cambridge UK)
What they are doing differently. Shift is not using Yamanaka factors at all. They built a proprietary single-cell aging clock and used it inside an AI simulation platform to search for safer rejuvenation genes that reverse epigenetic age without inducing the pluripotency pathways that carry tumor risk. The company has announced a single-gene target, SB000, which they describe as reversing markers of cellular aging without inducing dangerous pluripotency pathways. Total funding is approximately $18 million.
L-45 filter. If the single-gene approach holds up, the safety profile argument becomes substantially simpler than multi-factor Yamanaka approaches. A therapy that does not activate pluripotency pathways at all has a different regulatory conversation. For a 45-year-old thinking about therapies that might be accessible in 10 to 15 years, safety profile simplicity matters as much as mechanism.
Gate highlights. Gate 2 (Scientific Differentiation) scores high for novelty: their rejection of Yamanaka factors as the starting point is a genuine scientific bet, not a variation on existing approaches. Gate 1 (Leadership) requires more work: strong technical credentials but limited commercial biotech track record at the executive level.
One thing to watch. Peer-reviewed publication of SB000 data. Company-reported claims are the starting point. Independent scientific validation is the Gate 2 trigger that changes the score.
5. Retro Biosciences (private, Redwood City)
What they are doing differently. Sam Altman-backed with a stated goal of adding 10 years to the human lifespan. Their lead candidate RTR242 is a small molecule targeting lysosomal function, the cellular recycling process called autophagy that breaks down damaged proteins and organelles. RTR242 entered first-in-human testing in late 2025 and early 2026. They are also running a stem cell reprogramming program and an OpenAI collaboration on AI-designed proteins, with the two companies announcing a reported approximately 50x increase in expression of stem cell reprogramming markers using their custom model in August 2025.
L-45 filter. Autophagy decline is one of the earliest measurable changes in aging biology and begins in the 40s in otherwise healthy individuals. The buildup of protein aggregates that impaired autophagy allows to accumulate is upstream of neurodegeneration, cardiovascular disease, and metabolic dysfunction. RTR242 targets this at the mechanism level rather than treating downstream symptoms.
Gate highlights. Gate 5 (Market Size) scores very high if the autophagy-restoration thesis holds across organ systems. Gate 2 (Clinical Data) is now early-stage human rather than preclinical only, which improves the composite score relative to the rest of this list. RTR242 in first-in-human testing is meaningful stage differentiation.
One thing to watch. Initial safety and pharmacodynamic data from the RTR242 human study. That readout will tell the field whether restoring lysosomal function is safe and whether the target engagement signals match what preclinical models predicted.
The One Public Name
There are very few publicly listed companies explicitly positioning themselves around longevity gene therapy as a core program. The clearest public pure-play I have found in this niche is Genflow Biosciences. They describe themselves as the first pure-play longevity company to list in Europe. They trade on the London Stock Exchange under GENF and on the OTCQB in the US under GENFF.
Their mechanism is different from Yamanaka-factor partial reprogramming. Genflow is delivering a centenarian variant of the SIRT6 gene using AAV vectors. SIRT6 is a sirtuin protein involved in DNA repair, telomere maintenance, and metabolic regulation. The centenarian variant was identified in individuals who lived past 100 with unusually healthy aging profiles. The thesis is that delivering this variant into aged cells mimics protective biology those individuals carry naturally.
That is scientifically credible. SIRT6 biology has a serious research base. Here is what the company actually looks like right now.
Market cap is in the range of approximately $10-13M US as of mid-March 2026, though it moves quickly at this size. Roughly $0.03 per share on the OTCQB. Five employees. No revenue. They called a shareholder meeting in March 2026 to authorize up to approximately 188.9 million new ordinary shares for a potential equity raise. OTC liquidity in the US is thin. The LSE listing is more active but still nano-cap. This is not a microcap. This is a nano-cap, and the dilution and governance risks are real and near-term.
Their lead program GF-1002 targets MASH as the primary regulatory pathway, which I think is a viable clinical strategy for getting a longevity gene therapy through the FDA. They completed dosing in a canine aging trial in December 2025 with no adverse events reported during administration. Initial efficacy data was expected in Q1 2026. A six-month efficacy read is expected June-July 2026. They also received approximately 4 million euros in non-dilutive funding from the Wallonia Region, a meaningful capital event for a company this size.
Against the 25-Gate system: Gate 2 (Clinical Data) scores low because everything is preclinical or canine stage, with no human efficacy data anywhere in the pipeline yet. Gate 5 (Market Size) scores well in concept across MASH, glaucoma, and sarcopenia. Gate 1 (Leadership) improved with the appointment of Gad Berdugo as chairman in early 2026, bringing 30 years of biotech corporate development and RNA-LNP experience. Gate 9 (Governance) carries the caution flag for all the structural reasons above. Gate 21 (Kill Switch) cannot be scored adequately from public information.
I am 52. I track my own biology. That means I owe you an honest read on a name like this, not a promotional one.
My view is that the June-July 2026 six-month canine readout is the trigger to watch. If the SIRT6 therapy shows measurable improvement in aged dog biomarkers without adverse signals, it is the first meaningful in-vivo efficacy validation of their core mechanism outside a mouse model. That result, if positive, changes the conversation about the IND pathway for MASH and sets up a more serious diligence conversation. That is when a full 25-Gate evaluation makes sense.
Until that readout, Genflow sits at the far end of my watchlist. Monitor, not allocate. The science is credible enough to track. The stage and structure require more evidence before it earns serious capital consideration under my framework.
What Would Change My View
A tumor-related adverse event in Life Biosciences' ER-100 trial would be the highest-consequence negative outcome for this entire category. Not because tumors would be unexpected in a novel gene therapy, but because it would confirm that removing c-Myc from the Yamanaka factor set does not adequately control oncogenic risk in humans. That result would reset timelines across every name on this list and likely collapse near-term investor appetite for the mechanism. I would not abandon the category on that outcome alone, but I would significantly revise every Gate 2 score downward and extend my time horizon by several years.
The two I am watching most closely are in the Microcap Target List with specific catalyst dates and the endpoints worth tracking. That list is in the Founder's Research Bundle. [https://everlifecapital.com/research-bundle/]
-Eric
Disclosure: EverLife Capital is an independent research publication. Articles reflect the author's opinions at the time of publication and are provided for informational and educational purposes only. They are not personalized investment advice, legal advice, or medical advice, and should not be construed as such. At publication, Eric Pemper does not hold positions in any of the public or private companies discussed in this article. He has not received compensation from any issuer, underwriter, dealer, or affiliated third party related to any security discussed. If either of those facts changes at the time of a future article discussing these companies, specific updated disclosure will be provided. Past performance is not indicative of future results. Investing in early-stage biotech involves substantial risk, including total loss of capital. Readers should conduct their own due diligence and consult qualified financial and medical advisors before making any investment or health-related decision.