Follistatin 315 vs VIP
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Immune SupportSleep Optimization
VIP- 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.
- VIP is a 28-amino acid neuropeptide with profound anti-inflammatory, vasodilatory, and immunomodulatory effects. It plays a critical role in gut motility, circadian rhythm, and immune tolerance. Used therapeutically for CIRS (Chronic Inflammatory Response Syndrome), MCAS, and inflammatory conditions.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- ~2 minutes in plasma (rapidly degraded by peptidases); intranasal delivery may extend local CNS effects
- Admin Route
- SubQ, IM
- Intranasal, SubQ, IV
- Research
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- Typical Dose
- No established human dosing protocol
- 50 mcg (4 sprays of 12.5 mcg each)
- Frequency
- Research use only
- 4x 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
- Potent anti-inflammatory for CIRS and mold illness
- Improves pulmonary hypertension symptoms
- Regulates gut motility and IBS symptoms
- Modulates circadian rhythm and sleep quality
- Reduces mast cell activation (MCAS)
- Improves cognitive function in neuroinflammatory conditions
- Vasodilatory — reduces vascular resistance
- 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
- Facial flushing (transient, intranasal)
- Mild nausea
- Headache at initiation
- Hypotension at high doses
- +1 more
- Stacks With
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