GHK Cu vs NAD+: Which Longevity Peptide Should You Take or Stack? PDF) GHK Cu may Prevent Oxidative Stress in Skin by Regulating Copper and Modifying Expression of Numerous Antioxidant Genes Does GHK Cu Really Work? 40 Years of Research Reviewed How GHK Peptide Works Signaling GHK acts as a switch for skin repair: Interacts with adenosine receptors reduces inflammation Activates MAPK ERK, PI3K Akt, TGF pathways Stimulates fibroblasts & keratinocytes boosts collagen, elastin