GHK Cu Peptide Serum 30 ml, Copper Peptide Serum with Hyaluronic Acid for Tightening, Collagen Boosting 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 2% GHK CU Copper Peptide Serum for Hair Growth and Scalp Care GHK Cu Copper Peptide Serum Private Label Skin Repair with Label