GHK Cu Hyaluronic Acid Gel Wells Pharmacy Network Copper Peptide Duo GHK Cu Anti Aging Serum & Moisturizer GHK Cu is a naturally occurring tripeptide in human plasma. Levels average 200 ng ml at age 20 and drop to 80 ng ml by age 60 (Pickart et al., 2020). That decline tracks with 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,