GHK Cu vs AHK Cu: Which Copper Peptide Is More Effective? I've been getting a lot of questions about GHK Cu, so here's a quick breakdown. GHK Cu is a copper peptide that naturally occurs in the body and plays a role in skin repair GHK Cu Peptide Therapy: The Definitive Clinical Guide to Gene Modulation, Protocols, and Efficacy GHK Cu is a small copper bound peptide (glycyl histidyl lysine with a copper ion) found naturally in human tissues and fluids. Its levels decline with age, and it plays a role in tissue repair, regeneration, GHK Cu Dosage and Protocol: A Medical Provider's Guide to the 30 Day Cycle Perfect B