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 Dimeric copper peptide incorporated hydrogel for promoting diabetic wound healing Nature Communications Copper tripeptide New insights on the skin stack I posted earlier this year. RECAPPING: GHK Cu was developed by a company called Procyte in the 90's. I was an interested follower of Dr. Pickart's work