GHK CU Beverly Hills Rejuvenation Center GHK Cu Copper Peptide Injections: Advanced Skin Rejuvenation GHK Cu (glycyl L histidyl L lysine) is a naturally occurring copper binding peptide found in human plasma. As levels decline with age, so may its support of the biological processes involved in collagen production, skin repair, and GHK Cu may Prevent Oxidative Stress in Skin by Regulating Copper and Modifying Expression of Numerous Antioxidant Genes