Spermidine vs Follistatin 315
Side-by-side comparison of key properties, dosing, and research.
Anti-Aging & LongevityCognitive Enhancement
SpermidineAnabolic & IGF
Follistatin 315- Summary
- Spermidine is a naturally occurring polyamine found in all living cells, with exceptionally high concentrations in wheat germ, aged cheese, and human sperm. It is the most studied autophagy-inducing dietary compound, shown to extend lifespan across multiple species and reduce cardiovascular and cognitive aging.
- 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.
- Half-Life
- ~30–60 minutes, but gut bacteria produce it continuously; supplementation raises tissue levels over weeks
- ~3–5 hours (longer systemic circulation vs FST-344)
- Admin Route
- Oral
- SubQ, IM
- Research
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- Typical Dose
- 1–5 mg
- No established human dosing protocol
- Frequency
- Once daily
- Research use only
- Key Benefits
- Induces autophagy — cellular self-cleaning
- Extends lifespan in yeast, flies, worms, and mice
- Reduces cardiovascular aging and arterial stiffness
- Reduces all-cause mortality (human epidemiological data)
- Neuroprotective: reduces amyloid and tau pathology
- Promotes hair growth (anagen phase activation)
- Reduces age-related immune decline
- Improves memory in aging models
- 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
- Side Effects
- Generally very well tolerated
- Rare: mild GI discomfort at high doses
- May temporarily reduce some gut bacteria species
- Rare: headache at initiation
- 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
- Stacks With
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