GHK-Cu is a natural peptide in human blood plasma, urine, and saliva. Research in animals reveals that GHK-Cu can improve wound healing, immune function, and skin health by stimulating collagen, fibroblasts and promoting blood vessel growth. There has been evidence that has shown that it acts as a feedback signal that is generated after tissue injury. It also suppresses free-radical damage and thus is a potent antioxidant.