Follistatin 315 vs GHRP-6
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Growth Hormone Peptides
GHRP-6- 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.
- GHRP-6 is the original synthetic GH-releasing peptide and a potent ghrelin receptor agonist. It produces strong GH pulses but is notorious for a significant hunger surge 30–45 minutes post-injection. This hunger side effect makes it less preferred than Ipamorelin or GHRP-2 for most protocols but can be useful in patients with appetite deficiency.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- 15–60 minutes
- Admin Route
- SubQ, IM
- SubQ, Intranasal
- Research
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- Typical Dose
- No established human dosing protocol
- 100–300 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
- Strong GH stimulation
- Elevated IGF-1
- Muscle growth and recovery support
- Potential anti-inflammatory effects at GI level
- Useful for patients with appetite deficiency or cachexia
- Enhanced recovery from training
- 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
- Intense hunger surge (30–45 min post-injection)
- Water retention
- Elevated cortisol (modest)
- Elevated prolactin (modest)
- +2 more
- Stacks With
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