FOXO4-DRI

Typical use cases

Dosing guidelines

Titration

Senolytics are typically described as intermittent "hit-and-run" agents rather than continuously titrated drugs; community protocols commonly report short pulsed cycles (e.g., several doses over a 1–2 week window, then a rest period) rather than steady daily escalation. No human titration schedule has been validated.

Reconstitution

Lyophilized powder reconstituted with bacteriostatic water for injection using sterile technique. A common community example: add ~2 mL bacteriostatic water to a 10 mg vial for a 5 mg/mL solution. Use clean technique to preserve sterility and peptide integrity.

Injection sites

Subcutaneous injection (e.g., abdomen, flank) is the route most often described in community protocols; foundational rodent research used intravenous (Baar 2017) or intraperitoneal (Zhang 2020) injection.

Storage & handling

Store lyophilized powder frozen (around -20 C) for long-term, or refrigerated at 2-8 C short-term; keep away from light. Store reconstituted solution refrigerated at 2-8 C and use within roughly 2-3 weeks.

Side effects

• Injection-site reaction (burning, itching, soreness) Mild · Common
• Fatigue / malaise Mild · Uncommon
• Transient inflammatory response from senescent-cell clearance Moderate · Uncommon
• Nausea Mild · Uncommon
• Muscle soreness Mild · Uncommon
• Off-target / non-selective cell death (theoretical; impaired wound healing) Severe · Rare

Research summary

The evidence base for FOXO4-DRI is entirely preclinical, with no completed human clinical trials. The foundational work is Baar et al. (Cell, 2017), which engineered a D-retro-inverso peptide that interferes with FOXO4's ability to sequester p53 in the nucleus of senescent cells; releasing p53 drives p53/p21-dependent and mitochondrial (BAX/caspase) apoptosis selectively in senescent cells while largely sparing healthy cells. In naturally aged mice, intravenous (retro-orbital) dosing at 5 mg/kg was reported to restore fur density, improve renal function and physical fitness, and accelerate recovery from doxorubicin-induced toxicity. Subsequent rodent work extended these observations to specific tissues; for example, Zhang et al. (Aging, 2020) reported that intraperitoneal FOXO4-DRI cleared senescent Leydig cells, reduced senescence-associated secretory phenotype (SASP) markers and inflammation, and partially restored age-related testosterone secretion in aged mice. More recent structural work (Nature Communications, 2025; PMC12216184) characterized how the disordered FOXO4-DRI peptide transiently binds the intrinsically disordered p53 transactivation domain (TAD2), with phosphorylation enhancing affinity, and optimized variants such as ES2 (Tripathi et al., eBioMedicine, 2021) have been reported as roughly 3–7-fold more potent than FOXO4-DRI. Important limitations: findings come from cell culture and mouse models only, effective doses and pharmacokinetics in humans are unknown, off-target senescent-cell clearance and systemic effects are not characterized in people, and the compound has no regulatory approval for human use. It remains strictly a research compound.

Key references

• https://pubmed.ncbi.nlm.nih.gov/28340339/
• https://pmc.ncbi.nlm.nih.gov/articles/PMC8601985/
• https://pmc.ncbi.nlm.nih.gov/articles/PMC12216184/
• https://www.aging-us.com/article/102682/text
• https://www.fightaging.org/archives/2026/02/people-are-still-working-on-the-senolytic-peptide-foxo4-dri/

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