Foxo4-DRI
Senolytic Peptide / D-isomer Retro-Inverso
Evidence grade 1 of 5, Untested. Read how the Atlas grades evidence.
The entire evidence base traces to a single 2017 Cell paper by Baar and de Keizer (Erasmus MC) showing that a FOXO4 D-retro-inverso peptide disrupts the FOXO4-p53 interaction and selectively clears senescent cells in aged and chemotoxicity-stressed mice, restoring fur density, renal function, and fitness. The only human-derived work is a 2021 Frontiers study by Huang and colleagues that applied the peptide to in-vitro expanded human chondrocytes in cell culture, not to human subjects. There are no completed or registered human clinical trials, so this is honestly animal-plus-in-vitro only, grade 1.
- FDA
- No FDA approval and no approved human indication; sold research-use-only, not for human consumption
- WADA
- Not prohibited
Reference only. Not medical advice.
What can go wrong
Zero human safety data of any kind; effects in complex human biology are unknown, and material is available only from gray-market research-chemical suppliers with no manufacturing or purity oversight.
Talk to a clinician before taking this. The Atlas can tell you what has been studied about Foxo4-DRI. It cannot tell you how it would interact with your body, your history, or anything else you are taking, and nothing on this page is a reason to start.
A D-isomer retro-inverso peptide that selectively triggers apoptosis in senescent ("zombie") cells while sparing healthy ones. Mice showed hair regrowth, restored stamina, and extended lifespan. There is no human data.
Selectively kills "zombie" senescent cells. Mice regrew hair and stamina. Human data: zero.
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
How it is supposed to work
FOXO4-DRI is a senolytic, a peptide designed to selectively kill senescent cells, the worn-out "zombie cells" that stop dividing but refuse to die, pile up with age, and leak inflammation that drives age-related disease. In a senescent cell, a protein called FOXO4 grabs the cell’s self-destruct switch, p53, and holds it captive in the nucleus, keeping the cell alive. FOXO4-DRI breaks that grip, freeing p53 to trigger the cell’s own programmed death. Because FOXO4 is barely present in healthy cells, it tends to pick off senescent cells while largely sparing the rest.
FOXO4-DRI is a D-Retro-Inverso peptide, built from mirror-image D-amino acids arranged in reverse order so it resists being broken down, and it is cell-penetrating. It is designed to mimic the part of FOXO4 that binds p53, letting it wedge into and disrupt the FOXO4-p53 interaction. That rational, structure-based design is part of why it became a flagship example of a senolytic peptide.
- Type
- Senolytic peptide (D-Retro-Inverso)
- Target
- FOXO4-p53 interaction
- Effect
- Kills senescent cells
- Evidence
- Mouse
- Human trials
- None
- Approved
- No
Cleared Aging Cells In Mice, Untested In Humans
FOXO4-DRI has a genuinely elegant, well-understood mechanism and a celebrated landmark result, paired with a near-total absence of human evidence. In a 2017 study, clearing senescent cells with it restored fitness, regrew fur, and improved kidney function in aged mice, and it even reversed some chemotherapy toxicity, a vivid proof-of-concept that made it a longevity-field star, and an active preclinical literature has since extended it to vascular aging and age-related testosterone decline. But the honest qualifiers are large. It is essentially all preclinical: there are no completed human trials of FOXO4-DRI, and the only senolytics tested in people so far are a few small molecules, not this peptide. Despite the excitement and a company formed to develop it, it has largely stalled. And there are real safety unknowns, because it works by triggering programmed cell death through p53, the body’s master tumor-suppressor, so manipulating it systemically is not trivial. Yet it is sold gray-market for longevity, years ahead of the evidence.
Safety in detail
All efficacy and tolerability evidence comes from mice (2017) and cultured human cells (2021); there are no human trials, so any human use is unvalidated and carries unquantified risk, including off-target apoptosis and unknown immunogenicity from a D-retro-inverso peptide.
- There is no human safety data, because FOXO4-DRI has not been tested in human trials.
- It works by triggering programmed cell death through p53, the master tumor-suppressor, so systemic manipulation carries real, unresolved risk.
- Senescent cells also have some beneficial roles, such as in wound healing, so broadly clearing them has unknown consequences.
- The encouraging selectivity and tolerability came from mice, not people.
- It is unapproved and stalled in development, and gray-market product is a complex, expensive peptide of uncertain quality.
Children and teenagers
FOXO4-DRI manipulates p53 and programmed cell death and has no human data, which makes it entirely inappropriate for minors, who carry little senescent-cell burden and for whom triggering apoptosis through a tumor-suppressor pathway is an unjustifiable risk. There is no appropriate pediatric use.
What people get wrong
Nothing recorded here yet. There is almost certainly something people get wrong about this one, and the blank space means we have not written it down, not that the record is clean.
Who profits, and who pushes back
Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.
FOXO4-DRI’s money runs through gray-market longevity-peptide vendors and anti-aging clinics selling it as a senolytic on the strength of the 2017 mouse study, while a company, Cleara Biotech, pursued the underlying biology in preclinical development. There is no approved product. The commercial pattern is familiar: a spectacular animal result functioning as marketing for an expensive peptide that has never been validated in humans.
How we got here
FOXO4-DRI originated in the laboratory of Peter de Keizer at Erasmus University Medical Center in Rotterdam and was first described in the March 2017 Cell paper by Marjolein Baar, de Keizer and colleagues, which engineered a D-retro-inverso peptide to block the FOXO4-p53 interaction that keeps senescent cells alive. The design used all mirror-image D-amino acids in reversed sequence to resist enzymatic breakdown while preserving target binding. To commercialize the academic finding, de Keizer co-founded Cleara Biotech, which as of 2026 remains preclinical and has shifted emphasis toward the FOXO4-p53 interaction more broadly rather than the original peptide; related groups such as Numeric Biotech have also engaged the target. No version of the molecule has entered human trials, yet the unpatented sequence circulates as a gray-market research chemical sold not for human consumption, so vendor and biohacking listings using names like 'senolytic peptide' describe material with no human safety data behind it.
As cellular senescence emerged as a driver of aging in the 2010s, senolytics, agents that clear senescent cells, became a major longevity strategy. The de Keizer lab designed FOXO4-DRI to break the FOXO4-p53 grip that keeps senescent cells alive, and its 2017 study, in which the peptide restored fitness, fur and kidney function in aged mice, made it a sensation. A company, Cleara Biotech, formed to develop the biology, and preclinical work continued into vascular and testosterone aging. But it largely stalled before human trials, even as gray-market sales for longevity proceeded on the original animal data.
- 2010sSenescence and senolytics emerge as a central aging strategy.
- 2017The landmark mouse study shows FOXO4-DRI restores fitness, fur and kidney function.
- late 2010sA company forms to develop the FOXO4-p53 biology commercially.
- 2020-2026Preclinical work extends to vascular and testosterone aging; structural studies refine the mechanism.
- ongoingIt stalls short of human trials while gray-market longevity use continues.
The numbers behind the grade
- Type
- Senolytic peptide
- Target
- FOXO4-p53
- Effect
- Clears senescent cells
- Evidence
- Mouse
- Human trials
- None
- Approved
- No
The people taking it
The flagship senolytic peptide, famous for a 2017 study in which it regrew fur and restored function in aged mice, a longevity-community favorite that remains entirely preclinical and stalled.
FOXO4-DRI’s users are early-adopter anti-aging and longevity biohackers drawn by the senolytic concept of clearing zombie cells and by the dramatic mouse results, along with age-related-decline-focused self-experimenters and a smaller chemo-recovery-curious group. It tends to attract affluent, science-aware experimenters willing to act far ahead of human evidence.
Used gray-market as an injectable senolytic for anti-aging on the strength of the 2017 mouse study, with no human data. Preclinical and not approved.
Set against the alternatives
Against the small-molecule senolytics like the dasatinib-plus-quercetin combination and fisetin, FOXO4-DRI is more targeted and elegant in mechanism but far less tested: those small molecules, not this peptide, account for the limited human senolytic data so far. Within the broader senolytic field, clearing senescent cells is a serious, legitimate aging strategy that works in animals, but human validation is early across the board, and FOXO4-DRI sits at the less-validated end. And against other longevity peptides like Epithalon, FOXO4-DRI is the senolytic flagship, distinguished by directly killing aged cells rather than tuning other pathways. Its strength is a rational, striking mechanism; its weakness is that the mechanism’s human payoff is entirely unproven.
What we do not know
- Whether FOXO4-DRI’s striking mouse results translate to humans, which no trial has tested.
- How safe systemic manipulation of p53 and apoptosis is in people.
- Why it stalled in development despite the early excitement.
- How it would compare with small-molecule senolytics that do have some human data.
What could change
Continued preclinical workResearch keeps extending it to new aging tissues and refining the mechanism.Path to human trialsWhether FOXO4-DRI or related FOXO4-p53 senolytics reach the clinic is the key question.Senolytic fieldBroader human validation of senolytics will shape its prospects.Gray-market persistenceLongevity sales continue well ahead of the evidence.
Legal status
FOXO4-DRI is not approved and has no completed human trials; it is a preclinical research compound. It is sold gray-market as an injectable senolytic for longevity, which is not an approved use. The broader senolytic field has only early human data, and none of it is for this peptide.
Status current as of July 2026. Regulatory positions change, sometimes quickly.
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Available only as gray-market research material, which is not for human use and lacks any human safety or efficacy data, while manipulating p53 carries real risk. There is no legitimate route. The senolytic concept is promising but early; those drawn to it should note that only small-molecule senolytics have any human data, and should treat FOXO4-DRI as experimental.
FOXO4-DRI is expensive as gray-market peptides go, reflecting its size and complexity. The cost buys an untested compound rather than a validated therapy, with no quality assurance behind most material.
Synthesized overseas, predominantly in China, as a complex peptide sold research-use-only, with quality varying widely and a certificate of analysis the only check, which cannot substitute for the human testing it lacks.
China and research vendorsThe source of gray-market FOXO4-DRI, a complex and expensive peptide, sold as research-use-only material.Preclinical developmentAcademic groups and a dedicated company pursue the FOXO4-p53 biology, still short of human trials.No approved supplyThere is no approved product and no clinical supply chain.
At a glance
- Action
- Senescent-cell apoptosis
- Mouse result
- Hair regrowth, stamina
- Human trials
- Zero
- Type
- Retro-inverso D-peptide
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Foxo4-DRI.
Nothing outstanding on this one.
Sources
Primary 2017 paper: FOXO4-DRI disrupts FOXO4-p53 interaction and selectively induces apoptosis in senescent cells, restoring fur, renal function and fitness in aged mice
Full-text of the foundational Cell paper: Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging
Only human-derived work: FOXO4-DRI selectively removed senescent cells from in-vitro expanded human chondrocytes (cell culture, not a human trial)
Huang Y, He Y, Makarcyzk MJ, Lin H, Frontiers in Bioengineering and Biotechnology 2021
PMC mirror confirming the 2021 chondrocyte study was in-vitro cell culture using cells from healthy donors, not administration to human subjects
Commercial lineage: Cleara Biotech was formed to commercialize the academic FOXO4-DRI work; as of 2026 it remains a preclinical concern focused on the FOXO4-p53 interaction rather than the original peptide, and no human trials of FOXO4-DRI have materialized
Cleara Biotech founded by Peter de Keizer is listed as the developer working on indications and optimizations of the FOXO4-p53 senolytic approach on the rejuvenation roadmap
Lifespan.io Rejuvenation Roadmap, Cleara Biotech / FOXO4-DRI
Not FDA approved, has no approved human indication, sold research-use-only and not for human consumption; no completed or registered human clinical trials as of 2026
Peptibase, FOXO4-DRI: What the Research Actually Shows (2026)
Design and mechanism summary: 43-amino-acid D-retro-inverso peptide, ~11-fold selectivity for senescent over healthy cells, developed at Erasmus MC Rotterdam, first described 2017
D-retro-inverso strategy (all D-amino acids, reversed sequence) confers protease resistance while preserving target binding; sold only through research-chemical suppliers
The studies that matter
Baar/de Keizer, Cell2017
The landmark study: clearing senescent cells with FOXO4-DRI restored fitness, regrew fur and improved kidney function in aged and fast-aging mice, and reversed some chemotherapy toxicity.
Mechanism work2017
Showed FOXO4 sequesters p53 to keep senescent cells alive, and that FOXO4-DRI releases p53 to trigger apoptosis selectively in those cells.
Leydig-cell aging study2020
In aged mice, FOXO4-DRI cleared senescent testosterone-producing cells and eased age-related testosterone decline.
Vascular aging studies2025-2026
FOXO4-DRI reduced senescence in blood-vessel cells and improved vascular function in aged mice.
Human clinical datanone
No completed human trials of FOXO4-DRI exist; the only senolytics tested in people are a few small molecules.