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 Amazon.com: Skin Perfection GHK Cu Copper Peptide Powder 99.7% Pure DIY Copper Peptides Serum for Face and Scalp Cosmetic Grade GHK Cu 1 Gram Creates Up to 100ml for Fuller Hair and By age 30, your skin produces about 25% less collagen. By 40, that number can reach 40%. This decline affects more than just how your skin looks. It changes how it heals, The Human Tripeptide GHKCu in Prevention of Oxidative Stress and Degenerative Conditions of Aging: Implications for Cognitive Health Pickart 2012 Oxidative Medicine and Cellular Longevity Wiley Online Library