Follistatin 315 vs Hexarelin
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Growth Hormone Peptides
Hexarelin- 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.
- Hexarelin is a potent synthetic GHRP and the strongest GH secretagogue in its class per unit dose. It also exhibits unique cardioprotective properties through direct binding to cardiac CD36 receptors, independent of GH release. Its potency is balanced by a tendency to desensitize GH release with prolonged use, making cycling important.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- ~70 minutes
- Admin Route
- SubQ, IM
- SubQ
- Research
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- Typical Dose
- No established human dosing protocol
- 100–200 mcg
- Frequency
- Research use only
- 2–3 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
- Strongest GH pulse per mcg among GHRPs
- Unique direct cardioprotective effects via CD36
- Increased IGF-1 and muscle anabolism
- Accelerated recovery from training
- Bone density support
- Anti-aging via GH axis
- Potential cardiac rehabilitation benefits
- 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
- Water retention
- Elevated cortisol
- Elevated prolactin (more pronounced than other GHRPs)
- Receptor desensitization with continuous use
- +1 more
- Stacks With
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