GHK Cu Copper Peptide 0.5% (topical foam) 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 Peptide Serum 30 ml, Copper Peptide Serum with Hyaluronic Acid for Tightening, Collagen Boosting GHK CU Topical Slide Case Holder Locking Top Etsy GHK CU Topical Serum 30ml Azur Skin