Essential GHK Cu Serum: What It Is, How It Works, and Why It Matters f Bacteriostaticwater.com 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 Ozark Have you heard of GHK Cu the copper peptide your body is already making? GHK Cu (Glycyl L Histidyl L Lysine Copper) is a naturally occurring tripeptide found in human plasma, saliva, and urine. Copper peptide GHK Cu Wikipedia