New — Free Peptide Starter Guide (2026): 13 chapters, 34 cited studies

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ToolsCompareFollistatin vs AHK-Cu

Follistatin vs AHK-Cu

Side-by-side comparison of key properties, dosing, and research.

Anabolic & IGF
Follistatin
Skin & CosmeticAnti-Aging & Longevity
AHK-Cu
Summary
Follistatin is an endogenous glycoprotein that acts as a potent inhibitor of myostatin and activin, two proteins that limit muscle growth. By binding and neutralizing myostatin, follistatin removes the primary brake on skeletal muscle hypertrophy, enabling significant muscle growth beyond normal physiological limits. It is distinct from its isoforms Follistatin 315 and Follistatin 344 in tissue distribution and binding affinity.
AHK-Cu is a copper tripeptide composed of alanine, histidine, and lysine chelated to copper. Distinct from GHK-Cu, AHK-Cu exhibits strong affinity for hair follicle receptors and demonstrates potent hair growth stimulation alongside wound healing and skin regeneration properties.
Half-Life
~3–5 hours (endogenous form)
Hours (topical, variable by formulation)
Admin Route
IM, SubQ
Topical, Scalp application, Subcutaneous (research)
Research
Typical Dose
50–100 mcg per injection site
0.01–0.1% concentration
Frequency
Every other day or 2–3x per week
Once or twice daily
Key Benefits
  • Potent myostatin inhibition enabling supraphysiological muscle growth
  • Increases skeletal muscle mass and fiber size
  • May accelerate recovery from muscle injury
  • Potential benefits in muscular dystrophy and sarcopenia
  • Synergistic with IGF-1 and growth hormone in anabolic protocols
  • Animal studies show dramatic increases in muscle mass
  • Reduces muscle fibrosis in dystrophic models
  • Stimulates hair follicle growth and reduces shedding
  • Increases dermal papilla cell proliferation
  • Promotes wound healing and skin regeneration
  • Antioxidant protection via superoxide dismutase activation
  • Improves skin elasticity and firmness
  • Supports collagen and elastin production
Side Effects
  • Potential for excessive muscle growth if doses are not controlled
  • FSH suppression with implications for fertility in women
  • Theoretical risk of cardiac hypertrophy with prolonged high-dose use
  • Limited human safety data available
  • +1 more
  • Generally well-tolerated topically
  • Mild scalp irritation or redness in sensitive individuals
  • Possible temporary hair shedding phase at treatment initiation
  • Copper accumulation with excessive systemic use (rare)
Stacks With