Expression and Purification of Recombinant GHK Tripeptides Are Able to Protect against Acute Cardiotoxicity from Exposure to Waterborne Copper in Zebrafish Wellness peptide craze: why people are injecting drugs 'not for human consumption' GHK Cu is getting a lot of attention right now, and for good reason. This is not just a skin peptide. It's a copper binding tripeptide with documented effects on gene expression, collagen synthesis, GHK Cu Youthful Skin, Healthy Cells, Vibrant You.