GHK cu is a copper peptide. It's great for skin, especially when you combine it with other things. My favorite is DMSO and derma rolling. My first experience with copper peptides was Procytes GHK cu is a copper peptide. It's great for skin, especially when you combine it with other things. My favorite is DMSO and derma rolling. My first experience with copper peptides was Procytes GHK Cu 200MG (Topical) Raw Amino GHKCu 50mg High Purity, U.S. Made Research Peptides OROS Research GHK CU 50mg OP Labs (Formerly Oxford Peptides)