Follistatin 315 vs Oxytocin
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Cognitive EnhancementSexual Health & Libido
Oxytocin- 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.
- Oxytocin is a 9-amino acid neuropeptide produced in the hypothalamus with diverse roles in social bonding, trust, stress reduction, and sexual function. Exogenous administration is used therapeutically to improve social cognition, reduce anxiety, and enhance intimacy.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- ~3–5 minutes (IV); ~30–60 minutes (intranasal, CNS effects persist longer)
- Admin Route
- SubQ, IM
- Intranasal, SubQ, IV
- Research
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- Typical Dose
- No established human dosing protocol
- 20–40 IU
- Frequency
- Research use only
- As needed (not daily long-term)
- 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
- Enhances social bonding and trust
- Reduces social anxiety and fear of rejection
- Improves autism spectrum symptoms (social cognition)
- Reduces cortisol and stress reactivity
- Enhances sexual arousal and intimacy
- Promotes maternal behavior and bonding
- May improve depressive symptoms
- Appetite suppression and metabolic effects
- 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 uterine cramping (avoid in pregnancy)
- Nasal irritation (intranasal)
- Headache
- Potential emotional over-attachment or jealousy amplification
- +2 more
- Stacks With
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