GHK Cu Copper Peptides: Topical vs Injectable GHK CU Peptide for Skin Rejuvenation Wittmer Rejuvenation Clinic 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 Amazon.com: Skin Perfection GHK Cu Copper Peptide Powder 99.7% Pure DIY Copper Peptides Serum for Face and Scalp Cosmetic Grade GHK Cu 1 Gram Creates Up to 100ml for Fuller Hair and Squalane + Copper Peptide (GHK Cu) Rapid Plumping Serum