GHK Cu is more than a skincare trend its a copper peptide involved in repair, regeneration, and cellular signaling., This peptide has been studied for its connection to collagen production, skin Site specific cross linking of collagen peptides by lysyl advanced glycation endproducts Chemical Communications (RSC Publishing) Full article: Physicochemical characterization of native glycyl l histidyl l lysine tripeptide for wound healing and anti aging: a preformulation study for dermal delivery Lysine Hydroxylation and Cross Linking of Collagen Springer Nature Link