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 Neurogan Health, GHK Cu Copper Peptide, Hair & Scalp Serum GHK Cu (copper peptide) is a science backed anti aging compound that supports collagen production, skin regeneration, and overall skin health. Used in both topical serums and subcutaneous Copper Peptide Duo GHK Cu Anti Aging Serum & Moisturizer