Tighten Dermatology Line Olympia Pharmaceuticals Peptides and Wellness Medications 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 12 weeks in, and my skin has NEVER looked better! GHK peptides are doing their thing. Alright, I need to give you an updateit's been 12 weeks since I started using GHK