Follistatin 315 vs Dihexa
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Cognitive Enhancement
Dihexa- 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.
- Dihexa is a potent experimental oligopeptide derived from angiotensin IV that dramatically enhances synaptogenesis. Preclinical research shows cognitive enhancement orders of magnitude more potent than BDNF — it is considered one of the most powerful nootropic compounds in research, but has very limited human safety data.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- Unknown (limited pharmacokinetic data)
- Admin Route
- SubQ, IM
- Oral, SubQ, Topical
- Research
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- Typical Dose
- No established human dosing protocol
- 5–10 mg
- Frequency
- Research use only
- 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
- Dramatically increases synapse formation (potentially 10 million× more potent than BDNF in animal models)
- Enhances memory and learning
- May reverse cognitive decline
- Improves neuroplasticity and executive function
- Long-lasting cognitive benefits from short courses
- Potential therapeutic agent for Alzheimer's
- 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
- Headache
- Irritability
- Brain fog during washout period
- Unknown long-term effects (insufficient data)
- Stacks With
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