Follistatin 315 vs Semax
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Cognitive Enhancement
Semax- 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.
- Semax is a synthetic heptapeptide derived from ACTH developed in Russia. It is a potent nootropic that enhances memory, focus, and provides neuroprotection. Approved in Russia for cognitive disorders, stroke recovery, and traumatic brain injury.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- Minutes (but effects persist for hours via BDNF induction)
- Admin Route
- SubQ, IM
- Intranasal, SubQ
- Research
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- Typical Dose
- No established human dosing protocol
- 0.25–1 mg (250–1000 mcg)
- Frequency
- Research use only
- 1–2 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
- Enhances memory and learning
- Improves focus and concentration
- Increases mental energy and motivation
- Provides neuroprotection via BDNF and NGF upregulation
- Reduces cognitive decline
- May alleviate ADHD symptoms
- Supports recovery from brain injury and stroke
- Fast-acting — effects within 30–60 minutes
- Approved in Russia for cognitive disorders and stroke recovery
- 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 (rare, often from higher doses)
- Anxiety or overstimulation at high doses
- Sleep disruption if dosed too late
- Irritability (uncommon)
- Stacks With
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