Copper Peptides for Skin: What GHK Cu Does and How It Compares to Retinol Ever heard of GHK Cu peptide? It's a naturally occurring copper peptide that helps repair tissue, stimulate collagen, and support skin healing. When used in injectable form, it works at a deeper level The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Page 1 Reviews Neurogan Health, Copper Peptide GHK CU, 120 mcg, 60 Tablets, 0.52 oz (15 g) iHerb