Class

Copper peptides

Copper peptides are short peptides that bind copper ions. GHK is a tripeptide that binds copper(II), and the GHK-Cu complex has been proposed to act in tissue repair and skin remodelling, for example by stimulating collagen, decorin and glycosaminoglycan synthesis in cell and tissue models. Copper is a cofactor for the lysyl oxidase enzymes that cross-link collagen, which a 2026 review discusses as a mechanistic hypothesis. Plasma GHK levels have been reported to decline with age.

How the members differ

Apo-GHK, GHK-Cu and other copper peptides are not interchangeable, and copper occupancy and stability vary with formulation.
AHK-Cu, which has alanine in place of glycine, has been studied mainly for hair follicles in the lab, while GHK-Cu has broader skin and wound research.
Human data for GHK-Cu come from small topical studies; no controlled trial of injected or oral GHK-Cu was found.

Compounds in this group

GHK-CuLimited human data · Not approved — research use onlyGHK-Cu is the copper(II) complex of the naturally occurring tripeptide glycyl-histidyl-lysine. It has been examined in cell, tissue and animal models of wound repair and gene expression, with only small human studies of topical cosmetic products. It is not an approved drug.

For research use only. Not for human or veterinary use. Not a drug, food, or dietary supplement. Mechanism descriptions summarize published research and are not claims of effect in people.