FOXO4-DRI
Senolytic peptide
A synthetic peptide studied in senolytic and cellular-aging research.
Also referenced as: Proxofim, FOXO4 D-Retro-Inverso, FOX04-DRI
Overview
FOXO4-DRI is a synthetic, retro-inverso (D-amino acid) peptide designed by researchers (notably from the group of Peter de Keizer) based on the FOXO4 sequence that interacts with p53. It was engineered as a proof-of-concept senolytic to target senescent cells.
At a glance
What FOXO4-DRI does
FOXO4-DRI is a synthetic senolytic peptide built as a D-amino-acid retro-inverso (hence 'DRI') mimic of a segment of the FOXO4 transcription factor. Its single, precise job is to disrupt the protein-protein interaction between FOXO4 and p53 inside senescent cells. In cells that have entered senescence, FOXO4 sequesters p53 in the nucleus, and this interaction keeps the senescent cell alive despite its damage. FOXO4-DRI competitively displaces p53 from FOXO4, causing p53 to be excluded from the nucleus and relocated in a way that unleashes the intrinsic (mitochondrial) apoptosis pathway.
The therapeutically attractive feature is selectivity: healthy, dividing cells depend far less on the FOXO4-p53 survival axis, so they are largely spared, while 'zombie' senescent cells (which accumulate with age and secrete the inflammatory SASP) are pushed into programmed cell death. This is the defining mechanism of a targeted senolytic, distinct from broad cytotoxic agents.
All of the supporting evidence is preclinical. In cell culture, FOXO4-DRI selectively triggered apoptosis in senescent human chondrocytes, keloid fibroblasts (with documented p53-pSer15 nuclear exclusion), and endothelial cells. In mice, injection in both naturally aged and chemotherapy/irradiation-aged animals reduced senescent-cell burden, improved markers such as renal function, fitness, and fur density, suppressed aortic aging and improved aortic function, and in one study restored age-related testosterone secretion by clearing senescent Leydig cells. There are no completed large human clinical trials establishing safety and efficacy, so FOXO4-DRI should be understood as a promising experimental senolytic that has not yet been validated in people.
Effects reported in research
- Competitively disrupts the FOXO4-p53 protein interaction that keeps senescent cells alive, its defining and precise molecular action.
- Causes nuclear exclusion of p53 (documented via loss of p53-pSer15 in the nucleus), triggering intrinsic mitochondrial apoptosis in senescent cells.
- Selectively kills senescent cells while largely sparing healthy dividing cells, which depend less on the FOXO4-p53 axis (in-vitro/in-vivo).
- Selectively induced apoptosis in senescent human chondrocytes and keloid fibroblasts in culture (in-vitro).
- Reduced senescent endothelial-cell burden and modulated p53 signaling in vascular models (in-vitro).
- In naturally aged and induced-aging mice, reduced senescent-cell load and improved fitness, fur density, and renal function markers (preclinical).
- Suppressed aortic aging and improved aortic function in aged mice (preclinical).
- Restored age-related testosterone secretion by clearing senescent Leydig cells in aged mice (preclinical); no completed human trials establish safety or efficacy.
Effects listed reflect findings reported in the research literature — many in animal or in-vitro models. Listing an effect is not a claim of efficacy or a therapeutic indication in humans.
Mechanism of action
FOXO4-DRI is designed to competitively interfere with the interaction between FOXO4 and the tumor suppressor p53 in senescent cells. By disrupting FOXO4-p53 binding, it is reported to release p53 from the nucleus, triggering apoptosis preferentially in senescent cells (a senolytic effect). This mechanism was demonstrated in cell and mouse models; the retro-inverso D-amino acid design was intended to improve peptide stability.
Mechanistic description reflects published research-literature understanding. Much peptide research is preclinical (in-vitro or animal-model); mechanism in humans may differ and is not established for many compounds.
What it's studied for
Research contexts in which FOXO4-DRI appears in the literature. Listing a research area is not a claim of efficacy or a therapeutic indication.
Key characteristics
- A senolytic peptide targeting the FOXO4-p53 interaction
- Uses a retro-inverso (D-amino acid) design for stability
- Reported to induce apoptosis selectively in senescent cells
- Demonstrated in cell-culture and mouse studies
- No established human clinical trials; strictly preclinical
- Widely cited as a proof-of-concept senolytic peptide
Reported research dosing reference only
Educational reference, not dosing guidance. The figures below summarize amounts reported in published research and research-community protocols, provided for educational and research context only. They are not medical advice, not a recommendation, and not instructions for human use. FOXO4-DRI is a research compound.
Reported dosing is preclinical only, from rodent studies using intermittent (pulsed) administration rather than continuous dosing. These are reference figures for research context only, not dosing guidance for humans.
- Rodent studies: ~5 mg/kg intraperitoneal, given on an intermittent (e.g. every-other-day) pulsed schedule
- No established human research dose exists
Effects in mouse models were reported over roughly 10-14 days; the D-retro-inverso design extends the functional half-life from minutes to hours. Human pharmacokinetics are undefined.
How it compares
FOXO4-DRI is the only senolytic in this set, working by clearing senescent cells via FOXO4-p53 disruption, rather than acting on immune, mitochondrial, or pineal pathways.
Commonly studied alongside
Compounds frequently researched together with FOXO4-DRI in the literature. Cross-referenced for research context — not a usage or combination recommendation.
Compare and calculate
Side-by-side pages for the pairings the literature already documents for FOXO4-DRI, plus the unit-conversion reference for a reconstituted vial. Factual comparisons of documented characteristics — not a recommendation to combine or use any compound.
Handling & Stability
Lyophilized peptides are stored cold, protected from light, and reconstituted only at the time of intended in-vitro work.
- Avoid repeated freeze-thaw cycles
- Verify supplier lot and Certificate of Analysis
- Follow institutional lab-safety protocols
Analytical & COA Concepts
Reputable research suppliers publish a third-party Certificate of Analysis per batch. Key analytical concepts referenced in COAs include:
Category Context
FOXO4-DRI sits in the Longevity & Cellular area of the PeptiDex library.
- Entry type: Research compound reference
- Longevity & Cellular category hub →
- Browse the full library →
- Glossary of terms →
Where researchers source FOXO4-DRI
For researchers studying FOXO4-DRI, third-party suppliers such as Practically Natty Peptides offer research-grade material with third-party Certificates of Analysis and US-based shipping.
PeptiDex does not maintain a direct supplier listing for this compound. The link above goes to a third-party research-supplier directory.
Frequently asked questions
What is FOXO4-DRI?
FOXO4-DRI is a synthetic senolytic peptide designed as a D-retro-inverso (DRI) version of a FOXO4 fragment. It is studied for selectively clearing senescent ("zombie") cells by disrupting the FOXO4-p53 interaction, and it is a research-stage compound with no human clinical trials.
How does FOXO4-DRI work as a senolytic?
In senescent cells, FOXO4 binds and sequesters p53 in the nucleus, blocking apoptosis. FOXO4-DRI competitively disrupts this FOXO4-p53 interaction, releasing p53 to trigger apoptosis preferentially in senescent cells while reportedly sparing healthy cells in preclinical models.
What does 'D-retro-inverso' mean for this peptide?
D-retro-inverso means the sequence is reversed (retro) and built from D-amino acids instead of natural L-amino acids (inverso), which preserves the overall side-chain topology while greatly increasing resistance to proteolysis. This design extends functional stability from minutes to hours, enabling systemic dosing in preclinical models.
Is there human clinical evidence for FOXO4-DRI?
No. FOXO4-DRI is almost entirely preclinical, with the key evidence coming from mouse studies reporting senescent-cell clearance without overt toxicity. Any use outside animal or cell research is unsupported by clinical data, and it should be framed as experimental.
How is FOXO4-DRI studied in aging models?
Reported animal work used intermittent (pulsed) intraperitoneal dosing over a course of days, based on the idea that senolytics work by periodic clearance rather than continuous exposure. This intermittent design reflects the "hit-and-run" senolytic paradigm.
Answers are educational summaries of research-literature context and do not constitute medical advice. See the Research Library, COA guide, and Storage & Handling guide for more.
References
Primary literature indexed in PubMed for FOXO4-DRI. Listing a study records that it exists and is indexed — it is not a claim of efficacy, a therapeutic indication, or an endorsement of its conclusions. Much of this literature is preclinical (in-vitro or animal-model).
- Rejuvenation by Therapeutic Elimination of Senescent Cells
- The disordered p53 transactivation domain is the target of FOXO4 and the senolytic compound FOXO4-DRI
- FOXO4-DRI alleviates age-related testosterone secretion insufficiency by targeting senescent Leydig cells in aged mice
Each reference was checked against its PubMed record on 2026-07-28: the PMID resolves and the title, journal and year match. Where no indexed literature exists for a compound, PeptiDex says so rather than substituting a citation about a different molecule. See the editorial policy.