Intermediate Cu(II) Thiolate Species in the Reduction of Cu(II)GHK by Glutathione: A Handy Chelate for Biological Cu(II) Reduction Inorganic Chemistry GHK Cu Cooper Peptide: The Complete Skin & Repair Guide (2026) GHK Cu is the compound your body made at 25 and quietly stopped making. Most people find it in overpriced serums. Few understand what it actually does, or what happens when you're not GHK Cu (copper peptide) used topically is one of the most well studied skin repair peptides. Here's how it helps the skin, in practical terms: 1. Boosts collagen & elastin GHK Cu signals your skin