GHK-cu is a human copper-binding tri-peptide that is found in human plasma and released from tissues in case of injury. Copper peptide has been well-studied for aesthetic benefits such as hair regrowth, skin tightening, collagen deposition, wound healing, elastin production, glycosaminoglycan synthesis, and supporting the function of dermal fibroblasts. It has additionally shown benefit as a tissue repair agent for the lungs, bony tissue, liver, and stomach lining.