Copper tripeptide (GHK-CU) is a naturally occurring tripeptide first isolated from human plasma but also found in saliva and urine. During wound healing, Copper tripeptide can be removed from existing extracellular proteins by proteolysis and used as a chemoattractant for inflammatory and endothelial cells. Copper tripeptide increases the production of messenger RNA from collagen, elastin, proteoglycans and glycosaminoglycans in fibroblasts. Copper tripeptide is a natural regulator of various cellular pathways involved in skin regeneration.