AHK-Cu vs P21
Side-by-side comparison of key properties, dosing, and research.
- Summary
- 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.
- P21 is a synthetic peptide derived from CNTF (ciliary neurotrophic factor) that promotes hippocampal neurogenesis, enhances memory and spatial learning, and may reduce amyloid-beta pathology. It is used as a neurogenic and cognitive enhancer with potential anti-Alzheimer's applications.
- Half-Life
- Hours (topical, variable by formulation)
- Not well characterized; likely short, but neurogenic effects persist long after administration
- Admin Route
- Topical, Scalp application, Subcutaneous (research)
- SubQ, Intranasal
- Research
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- Typical Dose
- 0.01–0.1% concentration
- 100–500 mcg
- Frequency
- Once or twice daily
- Once daily
- Key Benefits
- 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
- Promotes hippocampal neurogenesis
- Enhances spatial memory and learning
- Increases BDNF expression
- Reduces amyloid-beta plaque formation (animal models)
- Anti-tau pathology potential
- Cognitive enhancement without stimulant effects
- Potential therapeutic for Alzheimer's and cognitive aging
- Side Effects
- 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)
- Generally well tolerated in animal studies
- Limited human clinical data
- Injection site reactions
- Potential mild fatigue at initiation
- Stacks With
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