Follistatin 315 vs Selank
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Cognitive Enhancement
Selank- 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.
- Selank is a synthetic heptapeptide analog of tuftsin developed in Russia. It is a potent anxiolytic that reduces anxiety and enhances cognitive function without sedation or addiction. It is approved for clinical use in Russia for anxiety disorders.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- Minutes (but effects persist for hours)
- Admin Route
- SubQ, IM
- SubQ, Intranasal
- Research
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- Typical Dose
- No established human dosing protocol
- 250–500 mcg
- Frequency
- Research use only
- 1–3 times daily
- 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
- Reduces anxiety without sedation
- Enhances memory and learning
- Improves focus and concentration
- Stabilizes mood
- Reduces physiological stress response
- May enhance motivation
- No addiction potential or withdrawal
- Fast-acting — effects within 20–30 minutes
- Approved clinically in Russia for anxiety disorders
- 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
- Mild sedation at higher doses (paradoxical)
- Fatigue (rare)
- Irritability during discontinuation (uncommon)
- Stacks With
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