GHK CU Peptide for Skin Rejuvenation Wittmer Rejuvenation Clinic Most people think skincare works at the surface level. But healthy skin function starts much deeper than a temporary glow. GHK Cu is a naturally occurring copper binding tripeptide that is already found Frontiers A Balanced Act: The Effects of GHGHRIGF1 Axis on Mitochondrial Function Frontiers Growth Hormone and Insulin Like Growth Factor Action in Reproductive Tissues