CalcMyPeptide
Anti-AgingAlso known as: FOXO4-D-Retro-Inverso, Proxofim

FOXO4-DRI

FOXO4-DRI (D-Retro-Inverso) is the vanguard of experimental senolytic therapy—a highly advanced, heavily engineered peptide designed exclusively to hunt down and obliterate "zombie" (senescent) cells. As tissues age or suffer severe oxidative stress, damaged cells refuse to die, instead secreting Senescence-Associated Secretory Phenotypes (SASP) that trigger massive systemic inflammation and aging. FOXO4-DRI selectively forces these toxic, age-causing cells to commit cellular suicide, dramatically reducing frailty, reversing organ dysfunction, and clearing the biochemical markers of advanced aging.

Reviewed by CalcMyPeptide Editorial Team
Last updated: April 2026Evidence: Low2 peer-reviewed citations

Quick Stats

Half-LifeExtended (DRI design resists proteases)
Dose Range5-20 mg/kg body weight
FrequencyEvery 3 days × 3 doses (protocol)
Vial Sizes10 mg, 50 mg
BioavailabilityIntraperitoneal or subcutaneous injection
Year Developed2017

Scientific Data

Molecular Formula
D-retro-inverso peptide (custom synthesis)
Molecular Weight
~3.1 kDa
PubChem ID
Developer
Peter de Keizer, Utrecht University

Mechanism of Action

FOXO4-DRI is a D-retro-inverso (DRI) peptide that selectively induces apoptosis (programmed cell death) in senescent cells while leaving healthy cells unharmed. It is the first rationally designed peptide-based senolytic.

In senescent cells, the FOXO4 transcription factor binds and sequesters p53 in the cytoplasm, preventing p53 from entering the nucleus and triggering apoptosis. Senescent cells are otherwise resistant to normal cell death despite accumulating DNA damage. FOXO4-DRI competes with endogenous FOXO4 for p53 binding, freeing p53 to translocate to the nucleus and activate apoptotic gene programs. The D-retro-inverso (mirror amino acid) design makes it resistant to protease degradation, enabling systemic activity.

In mouse studies, FOXO4-DRI reversed aging phenotypes including fur loss/discoloration, renal dysfunction, and physical frailty. Liver senescent cell burden was reduced significantly after just 3 doses. This is a landmark proof-of-concept for senolytic peptide therapy.

Source: PMID: 28340339

Background & History

FOXO4-DRI is a D-amino acid retro-inverso peptide designed to disrupt the interaction between FOXO4 and p53 inside senescent cells. Developed by Peter de Keizer at the Princess Máxima Center (Netherlands), it was published in Cell (2017) showing it selectively induced apoptosis in senescent cells — the first demonstration that targeted senolysis with a peptide was achievable. This landmark paper established FOXO4-DRI as a potentially transformative longevity compound. It specifically kills senescent cells (which drive aging via SASP) while leaving normal cells unaffected.

Research Use Cases

  • Cellular senescence clearance (senolytics) for longevity
  • Cancer treatment-induced accelerated aging reversal
  • Age-related pathology from SASP (senescence-associated secretory phenotype)
  • Frailty and physical decline associated with senescent cell burden

Dosing Protocol

Typical Dose5-20 mg/kg body weight
FrequencyEvery 3 days × 3 doses (protocol)
Half-Life~2-6 hours (estimated)
Common Vial Sizes10 mg, 50 mg

Dosing Protocols

Mouse-Derived Protocol (Human Translation)

Dose
5 mg/kg
Frequency
Every 3 days for 3 doses (SC or IP)
Note: Based on the published mouse protocol. Human translation is experimental. Very limited human data. Consult a longevity physician before use.

Body-Weight Dosing Reference

Estimated doses extrapolated from the published research range of 500020000 mcg/day (referenced to 70 kg / 154 lb). These are approximations — consult a qualified healthcare provider for personalised guidance.

WeightLowTargetHigh
120 lb(54 kg)3857 mcg9643 mcg15429 mcg
140 lb(63 kg)4500 mcg11250 mcg18000 mcg
160 lb(73 kg)5214 mcg13036 mcg20857 mcg
180 lb(82 kg)5857 mcg14643 mcg23429 mcg
200 lb(91 kg)6500 mcg16250 mcg26000 mcg
220 lb(100 kg)7143 mcg17857 mcg28571 mcg
250 lb(113 kg)8071 mcg20179 mcg32286 mcg

💉 For exact syringe units based on your vial concentration, use the FOXO4-DRI Reconstitution Calculator →

Administration

Route
Subcutaneous injection
Timing
Every 3 days (cycled protocol). No fasting required.
Fasting Required?
No — food timing not critical

Expected Timeline

Day 1-9 (3-dose cycle)
Senescent cell clearance. May cause transient inflammatory response (cytokine release from dying senescent cells).
Month 1-3
In animal models: restored fur quality, improved renal function, enhanced physical fitness. Human data pending.

Who Is It For?

Senolytic / Cellular Rejuvenation

Low

Most targeted senolytic peptide known. Proof-of-concept in mice is compelling, but human data is very limited.

Longevity Research

Low

Represents a new class of aging intervention. Suitable only for experimental longevity research use.

Reconstitution Example

Vial
10 mg
Water
2 mL
Concentration
5 mg/mL
Per Unit (100u syringe)
50 mcg
Dose of 5000 mcg = 100 units on a 100-unit insulin syringe

Safety & Considerations

Research peptide with very limited human data. Initial mouse studies are promising but not equivalent to human safety data. May cause transient inflammation as senescent cells are cleared. Not recommended for cancer patients. Very expensive custom synthesis. Completely experimental — use only under physician supervision.

Regulatory & Legal Status

FDA Status (US)
Research Only
WADA Status (2026)
Not Listed

Not currently on the WADA 2026 Prohibited List. Policies may change — verify before competition.

Classification

Research Chemical

US Compounding: Not eligible / not available

⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.

Interactions & Contraindications

Experimental compound — very limited human data. Induces apoptosis specifically in p21-positive senescent cells. Theoretical concern: some senescent cells serve protective roles (wound healing senescence, placental cells) — unknown impact with repeated dosing. Use infrequently (quarterly cycles per de Keizer protocol).

Synergies & Common Stacks

FOXO4-DRI clears existing senescent cells; Epitalon activates telomerase to prevent cells from becoming senescent via telomere erosion. Sequential senolytic + senomorphic protocol.

FOXO4-DRI removes senescent cells; NAD+ supports the healthy cells that replace them through SIRT1 and DNA repair mechanisms.

Dosing Quick Reference

FOXO4-DRI— Dosing Guide
Dose Range
5-20 mg/kg body weight
Half-Life
~2-6 hours (estimated)
Frequency
Every 3 days × 3 doses (protocol)
Route
Subcutaneous
10 mg vial50 mg vial
💧 2 mL BAC water📐 5 mg/mL concentration💉 50 mcg/unit (100u syringe)
Anti-Agingcalcmypeptide.com

Frequently Asked Questions

How does FOXO4-DRI kill senescent cells?
Senescent cells survive because FOXO4 traps p53, preventing it from triggering cell death. FOXO4-DRI competes with FOXO4 for p53 binding, freeing p53 to enter the nucleus and activate apoptosis. Healthy cells are unaffected — they don't rely on this FOXO4-p53 survival mechanism.
What is the FOXO4-DRI protocol?
The published mouse protocol: 5 mg/kg every 3 days for 3 doses (intraperitoneal). Human translation is not established — this is an experimental compound. Discuss with a longevity physician for individualized guidance.

References

  1. Baar MP, Brandt RMC, Putavet DA, Klein JDD, de Keizer PLJ et al. "Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis".” Cell (2017). PMID: 28340339

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