Peptide profile
FOXO4-DRI
Senolytic peptide targeting cellular senescence · also known as FOXO4, FOXO4-p21 peptide, Proxofim
Compare FOXO4-DRI with other peptides →Summary
FOXO4-DRI is a D-amino acid retro-inverso peptide designed to selectively induce apoptosis in senescent cells by disrupting the interaction between FOXO4 and p53. It belongs to a class of experimental senolytic compounds—agents that clear aged, dysfunctional 'zombie' cells from tissues. Research has been conducted primarily in mouse models, where it demonstrated improvements in fitness, fur density, kidney function, and lifespan metrics.
- Typical dose
- 1–2 mg per dose, typically 3 doses administered intermittently (e.g., every other day for one week per cycle) — NOTE: no validated human protocol exists; this is derived from mouse-model research only
- Half-life
- ~3–6 hours (estimated; no validated human pharmacokinetic data available)
- Route
- Subcutaneous, Intramuscular
- Cycle length
- 1 week on (3 injections EOD), repeated every 2–3 months — extrapolated from animal data
Mechanism
How it works
Senescent cells overexpress FOXO4, which binds to and sequesters p53 in the nucleus, preventing p53-mediated apoptosis and allowing senescent cells to persist and secrete pro-inflammatory cytokines (the senescence-associated secretory phenotype, or SASP). FOXO4-DRI is a competitive peptidomimetic that binds FOXO4 with high affinity, displacing p53 from the FOXO4 complex and restoring p53's ability to translocate to mitochondria where it triggers intrinsic apoptosis. Because normal, non-senescent cells do not rely on this FOXO4-p53 survival axis, the apoptotic effect is preferentially targeted to senescent cells.
Reported in research
Benefits
- Selective clearance of senescent ('zombie') cells from tissues (senolysis)
- Reduction of senescence-associated secretory phenotype (SASP) and systemic inflammation
- Demonstrated improvements in physical fitness, fur density, and renal function in aged mouse models
- Potential to slow or partially reverse aspects of tissue aging and age-related dysfunction
Context, not a prescription
Dosing
- Typical range
- 1–2 mg per dose, typically 3 doses administered intermittently (e.g., every other day for one week per cycle) — NOTE: no validated human protocol exists; this is derived from mouse-model research only (Subcutaneous, Intramuscular)
- Cycle length
- 1 week on (3 injections EOD), repeated every 2–3 months — extrapolated from animal data
- Half-life
- ~3–6 hours (estimated; no validated human pharmacokinetic data available)
Safety
Side effects & contraindications
Possible side effects
- Injection site pain or irritation
- Potential off-target apoptosis in non-senescent cells at supraphysiological doses
- Transient fatigue reported anecdotally in self-experimenters
- Unknown immunological responses in humans
- Possible disruption of beneficial paracrine senescent cell signaling (e.g., wound healing contexts)
Contraindications
- Active cancer or recent oncological treatment (senescent cells can play tumor-suppressive roles)
- Known hypersensitivity to peptidomimetic compounds
- Pregnancy or breastfeeding (no safety data)
- Active autoimmune disease (immune modulation risk)
- Use alongside cytotoxic chemotherapy without medical supervision
Research information, not medical advice. Always consult a licensed clinician before considering any peptide.
In depth
Full profile
What it does
In animal models: improved physical endurance, healthier-looking fur/skin, better kidney function, and reduced inflammatory markers. In human anecdotal reports: some describe improved energy, skin texture, and general vitality — though these are unverified and highly subjective.
How it works
Imagine your body as a city. Senescent cells are like condemned, hazardous buildings that the demolition crew (p53) wants to tear down, but a corrupt contractor (FOXO4) keeps blocking the order. FOXO4-DRI is like a legal injunction that removes the corrupt contractor, allowing demolition to proceed only on the condemned buildings.
When injected, the peptide travels through the bloodstream and selectively enters senescent cells where it interferes with a specific protein-protein interaction. This releases the cell's own internal self-destruct signal, causing the senescent cell to undergo programmed cell death (apoptosis). Healthy cells are largely unaffected because they don't rely on the same survival mechanism.
What to expect
Effects on senescent cell burden are not felt directly. Animal studies show measurable changes in biomarkers and physical function over weeks. Human experimentation reports are anecdotal — some self-experimenters report subjective improvements in energy over 2–6 weeks.
- Week 1 (Dosing Week): Three injections administered every other day. No immediate perceptible effects; the peptide is working at the cellular level to trigger apoptosis in senescent cells.
- Weeks 2–4: Potential subtle improvements in energy or inflammation levels as senescent cell burden begins to reduce. Effects are highly individual and not scientifically validated in humans.
- Weeks 4–8+: Animal studies show measurable tissue-level improvements by this point. In human self-experimentation, some report improved recovery, skin changes, or vitality — all anecdotal. Repeat cycles may be considered every 2–3 months.
Good to know
- Start with the lowest possible dose and monitor carefully for any adverse reactions
- Consult a physician familiar with peptide research before attempting any self-administration
- Never administer without proper reconstitution and sterile technique
Staying safe
- Injection site redness or soreness
- Temporary fatigue in the days following injection
Avoid if you have:
- Anyone with active cancer or a history of cancer
- Pregnant or breastfeeding individuals
- Anyone under 18 years of age
Mechanism of action
FOXO4-DRI is a D-amino acid retro-inverso peptidomimetic modeled on the FOXO4 CR3 domain (amino acids 150–180), which mediates interaction with the p53 DNA-binding domain. In senescent cells, FOXO4 is upregulated and constitutively localizes p53 to the nucleus via direct protein-protein interaction, preventing p53's cytoplasmic/mitochondrial pro-apoptotic function. FOXO4-DRI competitively displaces p53 from FOXO4, enabling p53 nuclear export and mitochondrial translocation, where it promotes Bax/Bak-dependent outer mitochondrial membrane permeabilization (MOMP), cytochrome c release, and caspase-9/caspase-3 activation via the intrinsic apoptotic pathway. The D-amino acid retro-inverso configuration confers proteolytic resistance, extending in vivo half-life relative to native L-peptides and enabling cellular penetrance.
Following subcutaneous or intraperitoneal administration, FOXO4-DRI distributes systemically. Its D-amino acid composition renders it resistant to serine/cysteine proteases, providing superior bioavailability compared to native peptides. The peptide crosses cell membranes via endocytic and direct membrane-transduction mechanisms. Its selectivity for senescent cells is attributable to the differential expression of FOXO4 — markedly upregulated in senescent vs. quiescent cells — and the reliance of senescent cells on the FOXO4-p53 survival axis, which normal proliferating or post-mitotic cells do not predominantly utilize for survival. Clearance is likely renal and hepatic with metabolites being peptide fragments of varying bioactivity.
Pharmacodynamics
Pharmacokinetically, peak plasma concentrations are expected within 30–60 minutes of subcutaneous injection given typical peptide absorption rates. Cellular apoptosis initiation is rapid post-internalization (hours), but measurable senescent cell clearance and downstream tissue remodeling in mouse models occurs over days to weeks. No human pharmacokinetic data exists.
In the Baar et al. 2017 Cell study: fast aging (XFE progeroid) and naturally aged mice showed significant restoration of physical fitness (grip strength, exercise endurance), improved renal function (reduced BUN), and fur density recovery. Histological analysis confirmed reduced p21+ and p16+ senescent cell burden in multiple tissues. SASP cytokine profiles (IL-6, IL-8 equivalents) were normalized. The retro-inverso configuration was essential for in vivo efficacy vs. the native L-amino acid version.
Timeline
- Days 1–3 (Dosing): Peak plasma concentrations achieved rapidly post-injection. Intracellular FOXO4-p53 complex disruption begins within hours. Initial apoptotic signaling cascade activation in high-FOXO4 expressing senescent cells. Some pro-inflammatory signaling possible as apoptotic bodies are cleared by phagocytes.
- Weeks 1–2: Progressive reduction in local senescent cell burden across injected and systemic tissues. Macrophage-mediated efferocytosis of apoptotic bodies. Potential transient elevation of clearing inflammatory cytokines before net SASP reduction. Tissue remodeling begins at sites of cleared senescent cells.
- Weeks 2–8+: In mouse models, measurable physiological improvements in fitness, tissue function, and inflammatory profiles manifest. Stem cell niche rejuvenation may occur secondary to senescent cell clearance. Long-term human effects entirely unknown. Repeat cycle candidacy depends on individual senescent cell re-accumulation kinetics.
Comparisons
- FOXO4-DRI — effectiveness High (murine; human unknown), safety Caution, cost $$$, High Complexity to use
- Dasatinib + Quercetin — effectiveness Moderate (limited Phase I human data), safety Moderate, cost $$, Medium to use
- Navitoclax (ABT-263) — effectiveness High (murine; hematologic toxicity concern), safety Caution, cost $$$$, High Complexity to use
Adverse effects
Common:
- Injection site reactions including erythema and induration — attributable to local immune response to foreign peptide
- Transient immune activation — potential cytokine release as apoptotic bodies from senescent cells are processed by macrophages
Rare:
- Off-target apoptosis in non-senescent cells expressing residual FOXO4 at supraphysiological doses — observed in mouse models at doses exceeding therapeutic windows
- Theoretical disruption of beneficial senescence in wound-healing contexts (acute senescence is pro-regenerative) — incidence unknown in humans
Contraindications & risk mitigation
Contraindicated in:
- Patients with active neoplastic disease — senescent cells provide tumor-suppressive paracrine signaling; clearance could theoretically alter tumor microenvironment
- Individuals on concurrent cytotoxic chemotherapy — additive apoptotic burden and unpredictable drug-drug interactions
- Patients with severe hepatorenal impairment — altered clearance kinetics and accumulation risk
- Individuals with p53 loss-of-function mutations — mechanism of action dependent on functional p53
- Implement intermittent low-dose protocols (3× EOD per cycle) rather than chronic dosing to minimize off-target apoptotic risk and allow tissue recovery between cycles
- Monitor inflammatory biomarkers (hsCRP, IL-6) and renal/hepatic function panels before and after each cycle
- Avoid concurrent use of other pro-apoptotic agents (navitoclax, ABT-263) without understanding additive senolytic burden
- Consider baseline senescent cell burden assessment (p16/p21 expression in peripheral blood mononuclear cells) to contextualize intervention
Qué hace
In animal models: improved physical endurance, healthier-looking fur/skin, better kidney function, and reduced inflammatory markers. In human anecdotal reports: some describe improved energy, skin texture, and general vitality — though these are unverified and highly subjective.
Cómo funciona
Imagine your body as a city. Senescent cells are like condemned, hazardous buildings that the demolition crew (p53) wants to tear down, but a corrupt contractor (FOXO4) keeps blocking the order. FOXO4-DRI is like a legal injunction that removes the corrupt contractor, allowing demolition to proceed only on the condemned buildings.
When injected, the peptide travels through the bloodstream and selectively enters senescent cells where it interferes with a specific protein-protein interaction. This releases the cell's own internal self-destruct signal, causing the senescent cell to undergo programmed cell death (apoptosis). Healthy cells are largely unaffected because they don't rely on the same survival mechanism.
Qué esperar
Effects on senescent cell burden are not felt directly. Animal studies show measurable changes in biomarkers and physical function over weeks. Human experimentation reports are anecdotal — some self-experimenters report subjective improvements in energy over 2–6 weeks.
- Week 1 (Dosing Week): Three injections administered every other day. No immediate perceptible effects; the peptide is working at the cellular level to trigger apoptosis in senescent cells.
- Weeks 2–4: Potential subtle improvements in energy or inflammation levels as senescent cell burden begins to reduce. Effects are highly individual and not scientifically validated in humans.
- Weeks 4–8+: Animal studies show measurable tissue-level improvements by this point. In human self-experimentation, some report improved recovery, skin changes, or vitality — all anecdotal. Repeat cycles may be considered every 2–3 months.
Bueno saber
- Start with the lowest possible dose and monitor carefully for any adverse reactions
- Consult a physician familiar with peptide research before attempting any self-administration
- Never administer without proper reconstitution and sterile technique
Manteniéndose seguro
- Injection site redness or soreness
- Temporary fatigue in the days following injection
Evitar si tienes:
- Anyone with active cancer or a history of cancer
- Pregnant or breastfeeding individuals
- Anyone under 18 years of age
Mecanismo de acción
FOXO4-DRI is a D-amino acid retro-inverso peptidomimetic modeled on the FOXO4 CR3 domain (amino acids 150–180), which mediates interaction with the p53 DNA-binding domain. In senescent cells, FOXO4 is upregulated and constitutively localizes p53 to the nucleus via direct protein-protein interaction, preventing p53's cytoplasmic/mitochondrial pro-apoptotic function. FOXO4-DRI competitively displaces p53 from FOXO4, enabling p53 nuclear export and mitochondrial translocation, where it promotes Bax/Bak-dependent outer mitochondrial membrane permeabilization (MOMP), cytochrome c release, and caspase-9/caspase-3 activation via the intrinsic apoptotic pathway. The D-amino acid retro-inverso configuration confers proteolytic resistance, extending in vivo half-life relative to native L-peptides and enabling cellular penetrance.
Following subcutaneous or intraperitoneal administration, FOXO4-DRI distributes systemically. Its D-amino acid composition renders it resistant to serine/cysteine proteases, providing superior bioavailability compared to native peptides. The peptide crosses cell membranes via endocytic and direct membrane-transduction mechanisms. Its selectivity for senescent cells is attributable to the differential expression of FOXO4 — markedly upregulated in senescent vs. quiescent cells — and the reliance of senescent cells on the FOXO4-p53 survival axis, which normal proliferating or post-mitotic cells do not predominantly utilize for survival. Clearance is likely renal and hepatic with metabolites being peptide fragments of varying bioactivity.
Farmacodinamia
Pharmacokinetically, peak plasma concentrations are expected within 30–60 minutes of subcutaneous injection given typical peptide absorption rates. Cellular apoptosis initiation is rapid post-internalization (hours), but measurable senescent cell clearance and downstream tissue remodeling in mouse models occurs over days to weeks. No human pharmacokinetic data exists.
In the Baar et al. 2017 Cell study: fast aging (XFE progeroid) and naturally aged mice showed significant restoration of physical fitness (grip strength, exercise endurance), improved renal function (reduced BUN), and fur density recovery. Histological analysis confirmed reduced p21+ and p16+ senescent cell burden in multiple tissues. SASP cytokine profiles (IL-6, IL-8 equivalents) were normalized. The retro-inverso configuration was essential for in vivo efficacy vs. the native L-amino acid version.
Cronología
- Days 1–3 (Dosing): Peak plasma concentrations achieved rapidly post-injection. Intracellular FOXO4-p53 complex disruption begins within hours. Initial apoptotic signaling cascade activation in high-FOXO4 expressing senescent cells. Some pro-inflammatory signaling possible as apoptotic bodies are cleared by phagocytes.
- Weeks 1–2: Progressive reduction in local senescent cell burden across injected and systemic tissues. Macrophage-mediated efferocytosis of apoptotic bodies. Potential transient elevation of clearing inflammatory cytokines before net SASP reduction. Tissue remodeling begins at sites of cleared senescent cells.
- Weeks 2–8+: In mouse models, measurable physiological improvements in fitness, tissue function, and inflammatory profiles manifest. Stem cell niche rejuvenation may occur secondary to senescent cell clearance. Long-term human effects entirely unknown. Repeat cycle candidacy depends on individual senescent cell re-accumulation kinetics.
Comparaciones
- FOXO4-DRI — efectividad High (murine; human unknown), seguridad Caution, costo $$$, High Complexity de usar
- Dasatinib + Quercetin — efectividad Moderate (limited Phase I human data), seguridad Moderate, costo $$, Medium de usar
- Navitoclax (ABT-263) — efectividad High (murine; hematologic toxicity concern), seguridad Caution, costo $$$$, High Complexity de usar
Efectos adversos
Comunes:
- Injection site reactions including erythema and induration — attributable to local immune response to foreign peptide
- Transient immune activation — potential cytokine release as apoptotic bodies from senescent cells are processed by macrophages
Raros:
- Off-target apoptosis in non-senescent cells expressing residual FOXO4 at supraphysiological doses — observed in mouse models at doses exceeding therapeutic windows
- Theoretical disruption of beneficial senescence in wound-healing contexts (acute senescence is pro-regenerative) — incidence unknown in humans
Contraindicaciones y mitigación de riesgos
Contraindicado en:
- Patients with active neoplastic disease — senescent cells provide tumor-suppressive paracrine signaling; clearance could theoretically alter tumor microenvironment
- Individuals on concurrent cytotoxic chemotherapy — additive apoptotic burden and unpredictable drug-drug interactions
- Patients with severe hepatorenal impairment — altered clearance kinetics and accumulation risk
- Individuals with p53 loss-of-function mutations — mechanism of action dependent on functional p53
- Implement intermittent low-dose protocols (3× EOD per cycle) rather than chronic dosing to minimize off-target apoptotic risk and allow tissue recovery between cycles
- Monitor inflammatory biomarkers (hsCRP, IL-6) and renal/hepatic function panels before and after each cycle
- Avoid concurrent use of other pro-apoptotic agents (navitoclax, ABT-263) without understanding additive senolytic burden
- Consider baseline senescent cell burden assessment (p16/p21 expression in peripheral blood mononuclear cells) to contextualize intervention
Reference data
Specifications
- Molecular formula
- C149H244N44O42S2 (approximate for the D-amino acid retro-inverso form)
- Molecular weight
- ~3462 Da (approximate)
- Half-life
- ~3–6 hours (estimated; no validated human pharmacokinetic data available)
- Route
- Subcutaneous, Intramuscular
- Cycle length
- 1 week on (3 injections EOD), repeated every 2–3 months — extrapolated from animal data
- Storage
- Store lyophilized powder at -20°C away from light and moisture. Once reconstituted with bacteriostatic water, store at 4°C and use within 7–14 days. Avoid repeated freeze-thaw cycles.
- Legal status
- Unscheduled research chemical in most jurisdictions; not approved by FDA, EMA, or any regulatory body for human use. Legal to purchase for research purposes in the United States; regulations vary internationally.
FAQ
Common questions
What is the evidence base for FOXO4-DRI, and how strong is it?
The primary and seminal publication is Baar et al. (2017) in Cell (doi:10.1016/j.cell.2017.02.031), demonstrating selective senescent cell apoptosis and functional restoration in XFE progeroid and naturally aged mouse models. This is a single peer-reviewed study in a high-impact journal with no published human clinical trials as of 2024. The evidence is categorized as animal-grade; extrapolation to humans is speculative.
How does FOXO4-DRI compare mechanistically to other senolytics like Dasatinib+Quercetin or Navitoclax?
Dasatinib+Quercetin operates via BCL-2 family inhibition and tyrosine kinase inhibition with broader anti-apoptotic target profiles; Navitoclax (ABT-263) directly inhibits BCL-2/BCL-XL/BCL-W causing thrombocytopenia as a significant off-target effect. FOXO4-DRI's mechanism is more upstream and theoretically more selective, targeting the FOXO4-p53 survival axis unique to senescent cell persistence. However, selectivity has only been validated in mouse models and may differ across human tissue senescence heterogeneity.
Does the D-amino acid retro-inverso configuration affect immunogenicity?
D-amino acid peptides are generally less immunogenic than L-peptides because proteasomal processing and MHC-II presentation require L-amino acid substrates. However, they are not non-immunogenic — alternative presentation pathways exist and individual immune responses vary. Immunogenicity profiling in humans has not been published for FOXO4-DRI.
What is the evidence level?
This compound is classified as Animal data. Most data comes from preclinical animal studies. Human clinical trial evidence is limited or absent.
Research
Research & sources
Current evidence for FOXO4-DRI is rated as Animal data. Research is based primarily on animal models.
- 1. Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging (2017) — Cell. 169(1):132-147.e13. Baar MP et al. doi:10.1016/j.cell.2017.02.031
- 2. Senolytics in idiopathic pulmonary fibrosis: Results from a first-in-human, open-label, pilot study (2019) — EBioMedicine. 40:554-563. Kirkland JL et al. doi:10.1016/j.ebiom.2018.12.052 (Dasatinib+Quercetin, not FOXO4-DRI, cited for senolytic human context)
- 3. The role of senescent cells in ageing (2014) — Nature. 509:439-446. van Deursen JM. doi:10.1038/nature13193
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