Follistatin 315 vs Pal-AHK
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Skin & CosmeticAnti-Aging & Longevity
Pal-AHK- 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.
- Pal-AHK is the palmitoylated form of the AHK-Cu copper tripeptide, created by attaching a palmitic acid chain to enhance skin penetration and lipid bilayer affinity. The palmitoyl modification significantly improves dermal bioavailability compared to unmodified AHK, making it particularly effective in anti-aging and hair growth formulations.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- Extended (lipid depot effect in stratum corneum)
- Admin Route
- SubQ, IM
- Topical
- Research
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- Typical Dose
- No established human dosing protocol
- 0.01–0.05% in formulation
- Frequency
- Research use only
- Once or twice 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
- Enhanced skin penetration vs. unmodified AHK-Cu
- Stimulates dermal collagen and elastin production
- Promotes hair follicle anagen phase
- Antioxidant and wound healing activity
- Firming and plumping effect on aging skin
- Improved bioavailability via lipid bilayer incorporation
- 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
- Generally well-tolerated
- Mild irritation at high concentrations in sensitive skin
- Possible comedogenicity at very high palmitate concentrations (formulation-dependent)
- Stacks With
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