P21 vs AHK-Cu
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
P21
P21 is a synthetic peptide derived from Cerebrolysin, specifically designed to mimic the neurotrophic effects of the parent compound. It promotes neurogenesis and has shown cognitive-enhancing properties in research.
Full details →AHK-Cu
AHK-Cu (Copper Tripeptide-3, Alanine-Histidine-Lysine Copper) is a copper peptide similar to GHK-Cu but with different properties. It's used for hair growth and skin rejuvenation applications.
Full details →Side-by-Side Comparison
| Aspect | P21 | AHK-Cu |
|---|---|---|
| Mechanism | Inhibits glycogen synthase kinase-3β (GSK-3β) and activates CREB signaling pathway. This promotes BDNF expression, neurogenesis in the hippocampus, and synaptic plasticity. | The copper-binding tripeptide stimulates collagen synthesis and may promote hair follicle enlargement. Works similarly to GHK-Cu but may have distinct receptor interactions. |
| Typical Dosage | Research protocols typically use 1-5mg administered intranasally or subcutaneously. Often used in cycles of 2-4 weeks. | Topical: 0.5-2% concentration in serums for skin or scalp applications. Often combined with other growth factors for hair formulations. |
| Administration | Can be administered intranasally for direct CNS access or subcutaneously. Best used cyclically rather than continuously. | Topical application to skin or scalp. Can be used with microneedling for enhanced penetration. May cause temporary blue-green tint at high concentrations. |
| Side Effects | Limited data. Reported effects include mild headache, temporary brain fog during initial use, and fatigue. | Generally well-tolerated. May cause skin irritation in sensitive individuals. Temporary discoloration possible. |
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