GHK Cu Copper Peptide Injections: Advanced Skin Rejuvenation GHK Cu as a multifunctional copper peptide: synthesis routes, process engineering and emerging applications Systems Microbiology and Biomanufacturing Springer Nature Link A Dermatologist's Take on the Copper Peptide (GHK Cu) Trend By age 30, your skin produces about 25% less collagen. By 40, that number can reach 40%. This decline affects more than just how your skin looks. It changes how it heals,