Follistatin 315 vs DSIP
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Sleep OptimizationCognitive Enhancement
DSIP- 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.
- DSIP is an endogenous neuropeptide originally isolated from rabbit cerebrospinal fluid that induces delta-wave (deep) sleep. It also modulates stress response, cortisol regulation, and LH secretion, making it valuable for sleep optimization and stress management.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- ~30–60 minutes; however downstream sleep effects last 4–6 hours
- Admin Route
- SubQ, IM
- SubQ, IV, Intranasal
- Research
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- Typical Dose
- No established human dosing protocol
- 100–400 mcg
- Frequency
- Research use only
- Once nightly
- 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
- Induces and deepens delta-wave (slow-wave) sleep
- Reduces cortisol and normalizes HPA axis
- Improves sleep quality in insomnia patients
- Anti-stress and anxiolytic effects
- May improve opiate/alcohol withdrawal symptoms
- Analgesic properties through opioid modulation
- Antioxidant and neuroprotective 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
- Generally well tolerated
- Mild grogginess next morning at higher doses
- Rare: hypotension
- Potential for altered dream patterns
- Stacks With
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