Copper peptides explained what are the differences between copper peptides and GHK CU peptides? What they actually do for the skin in terms of repair and collagen, and what you can and cant mix Copper Tri Peptide (GHK Cu) is one of the most researched peptides in skincare, and for good reason. It's a naturally occurring peptide that helps signal the skin to repair and regenerate. As we GHK Cu Peptide Foundry Premium Research Peptides Injectable GHK Cu: Beginner's Guide to Copper Peptide