What is the main difference between GHK-Cu and AHK-Cu?

GHK-Cu is Copper tripeptide-1, Gly-His-Lys-Cu. AHK-Cu is Alanine-histidine-lysine copper peptide. They differ in evidence tier (Clinical versus Limited), half-life (Short systemically versus Short systemically) and the doses reported in research.

Can you use GHK-Cu and AHK-Cu together?

They are commonly combined in research-community protocols, and blends containing both exist. There is no published human trial of the combination, so there is no established dosing for it.

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GHK-Cu vs AHK-Cu

Two copper tripeptides with different sequences and very different amounts of published work.

Two routes for AHK-Cu. AHK-Cu can be applied topically in a serum or injected subcutaneously, and the two are not interchangeable. The subcutaneous figures mirror GHK-Cu, the closely related copper tripeptide — there is no AHK-Cu-specific injection trial, so treat them as extrapolated from a structural analogue.

Pick one route and stay on it. The topical route puts the whole vial into a 30 mL serum; the subcutaneous route uses bacteriostatic water and the dose table. See the AHK-Cu page.

The short version

GHK-Cu has decades of cosmetic literature. AHK-Cu has very little. Both bind copper and both are studied topically, but GHK-Cu sits in our clinical tier on the strength of published human cosmetic work, while AHK-Cu is graded limited.

	GHK-Cu	AHK-Cu
What it is	Copper tripeptide-1, Gly-His-Lys-Cu	Alanine-histidine-lysine copper peptide
Evidence tier	Clinical	Limited
Route	Subcutaneous	Topical or subcutaneous
Half-life	Short systemically	Short systemically
Vial sizes	50/100 mg	100 mg
Water we suggest	3 mL, 3 mL	standard rule
Reported doses	1 mg, 2 mg, 3 mg	1 mg, 2 mg
Has a schedule	no	no

Different sequences, different focus

GHK-Cu is glycyl-histidyl-lysine; AHK-Cu is alanyl-histidyl-lysine. Most AHK-Cu work is in-vitro and hair-follicle focused, which is why it is usually discussed for hair rather than skin.

Both are mostly topical

The published record for both is dominated by topical formulation work rather than systemic administration. Reconstituted injection figures are community convention, not trial doses.

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