Copper Peptides for Skin: The Science, Benefits, and Best Practices Hubmed Frontiers Growth hormone insulin like growth factor I axis in health and disease states: an update on the role of intra portal insulin Before vs. after 3 months of GHK Cu peptide therapy smoother texture, more even tone, and skin that looks healthier overall. Small peptide, big difference GHK Cu Peptide Progress: Week 3 Results