AHK-Cu is the copper(II) complex of the tripeptide L-alanyl-L-histidyl-L-lysine (Ala-His-Lys). It is a close analogue of GHK-Cu, differing only in the N-terminal residue, alanine in place of glycine; both peptides carry the N-terminal Xxx-His arrangement that forms a well-characterised class of copper(II) binding sites. Published research specific to AHK-Cu is very limited. The principal study examined human hair follicles in organ culture and cultured dermal papilla cells. Related work has examined a vitamin C-conjugated AHK peptide, without copper, in a myoblast cell line, and the copper coordination chemistry of peptides with the same binding motif.