Defy 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 GHK Cu Copper Peptide Injections: Advanced Skin Rejuvenation GHK Cu Peptide Serum, Copper Peptide Serum with Hyaluronic Acid for Skin Tightening, Collagen Boosting & Deep Hydration, Advanced Topical Anti Aging Facial Serum TikTok Shop GHK Cu: Skin Benefits GHK Cu is a copper peptide studied for its role in supporting collagen production, skin repair, and anti oxidant activity. Research suggests it may help improve skin firmness, elasticity, and overall