Follistatin 315 vs GHK
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Skin & CosmeticAnti-Aging & Longevity
GHK- 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.
- GHK is the natural tripeptide (Gly-His-Lys) released from human albumin that activates tissue remodeling, collagen synthesis, and anti-aging gene expression. The copper-free form is the biological signaling molecule; it chelates copper in tissue to form GHK-Cu but also has independent biological activity.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- Extremely short as free peptide; tissue binding extends local effects
- Admin Route
- SubQ, IM
- SubQ, Topical, Oral
- Research
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- Typical Dose
- No established human dosing protocol
- 100–500 mcg
- Frequency
- Research use only
- Daily or 5x per week
- 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
- Stimulates collagen and extracellular matrix synthesis
- Activates tissue repair gene expression programs
- Anti-aging: reverses 57% of age-related gene changes
- Antioxidant and anti-inflammatory
- Wound healing and skin barrier repair
- Improves skin laxity, texture, and radiance
- Neuroprotective (stimulates NGF, BDNF)
- Anti-fibrotic in liver and lung models
- 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
- Excellent safety profile (naturally occurring peptide)
- Rare: mild injection site reaction (SC)
- No significant adverse effects identified in research
- Stacks With
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