Follistatin 315 vs FOXO4-DRI
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Anti-Aging & Longevity
FOXO4-DRI- Summary
- Follistatin 315 is a splice variant isoform of follistatin produced by alternative mRNA processing. Unlike Follistatin 344 which is tethered to cell surfaces via heparan sulfate proteoglycans, FST-315 circulates freely in the bloodstream and has broader systemic distribution. It is the predominant circulating form and exerts systemic myostatin inhibition as well as FSH suppression, making it relevant to both muscle growth and reproductive endocrinology.
- FOXO4-DRI is a D-retro-inverso peptide derived from the FOXO4 protein that selectively induces apoptosis in senescent cells. By disrupting the FOXO4-p53 interaction that keeps senescent cells alive, it triggers programmed cell death specifically in these aging, pro-inflammatory cells while sparing healthy tissue.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- Estimated 2-4 hours (D-amino acid confers resistance to proteolysis)
- Admin Route
- SubQ, IM
- Subcutaneous, Intraperitoneal (research)
- Research
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- Typical Dose
- No established human dosing protocol
- 5 mg/kg in rodent studies; human equivalent approximately 0.5-1 mg/kg
- Frequency
- Research use only
- 3 consecutive days per cycle
- Key Benefits
- Systemic myostatin inhibition for whole-body muscle growth
- Freely circulating — broader tissue distribution than FST-344
- Strong FSH-suppressive activity useful in certain hormonal protocols
- Potential for greater anabolic effect across multiple muscle groups simultaneously
- May be more relevant to reproductive endocrinology applications
- Studied in gene therapy approaches for muscular dystrophy
- Selectively clears senescent cells (senolytics)
- Reduces senescence-associated secretory phenotype (SASP) and chronic inflammation
- Demonstrated restoration of physical fitness in aged mice
- May improve healthspan and reduce age-related tissue dysfunction
- Potential for treatment of age-related pathologies driven by cellular senescence
- Does not affect healthy non-senescent cells at therapeutic doses
- Side Effects
- Systemic FSH suppression — significant concern for fertility
- Greater potential for off-target effects vs FST-344 due to systemic distribution
- Limited human safety data
- Potential cardiac hypertrophy with prolonged high-dose exposure
- Limited human data; largely preclinical evidence
- Possible temporary inflammatory response as senescent cells are cleared (senolytic effect)
- Weight loss observed at high doses in rodent studies
- Unknown long-term safety profile in humans
- Stacks With
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