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 Beverly Hills Rejuvenation Center Essential GHK Cu Serum: What It Is, How It Works, and Why It Matters f Bacteriostaticwater.com The naturally occurring peptide GHK reverses age related fibrosis by modulating myofibroblast function He Aging Pathobiology and Therapeutics