Viral claim says GHK Cu reset nearly 4,000 genes to a younger state and increased collagen production in a preclinical study. This refers to research on GHK Cu, a naturally occurring copper binding peptide that Growth Hormone and Aging Endotext NCBI Bookshelf Human Growth Hormone Therapy HRT HealthGAINS 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,