Expression and Purification of Recombinant GHK Tripeptides Are Able to Protect against Acute Cardiotoxicity from Exposure to Waterborne Copper in Zebrafish Frontiers Exploring the beneficial effects of GHK Cu on an experimental model of colitis and the underlying mechanisms The FDA is now reconsidering 12 peptides it previously placed in Category 2, a designation that blocks compounding pharmacies from producing them. The reasoning centers on safety concerns and limited data, but The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline GHK Cu Topical vs Injection Which is the Better Copper Peptide Form?