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 Skincare Products SumaNurica Skin Perfection GHK Cu Copper Peptide Serum Booster, 1 Percent Blue Liquid For Face, Neck, Body, Hair, And Scalp, 0.5 oz Walmart.com Amazon.com: Skin Perfection Copper Peptide Serum GHK CU 1% for Face & Hair Copper Peptides for Skin, Hair, & Scalp 1% Blue Liquid for Face, Neck, Body, Scalp Multi Use Serum Booster with