GHK Cu Copper Peptide Neck & Face Serum GHK CU Topical Serum 30mL 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 Peptide Dosage Calculator (Reconstitution) 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