I was super skeptical because I've literally tried everything Retinol destroyed my skin. Vitamin C oxidized and stung. Four different peptide serums and nothing actually worked. Then I tried GHK Cu. 6 weeks GHK Cu Skin Serum Peptide Rejuvenation GOAL.MD Copper Peptides & Retinol Can They Be Used Together? Yes, you can use Copper Peptides & Retinol just be smart about it! Retinol = speeds up cell renewal Copper peptides = support Copper Peptide (GHK Cu) 2% Recovery Serum Copper Peptides for Skin: What GHK Cu Does and How It Compares to Retinol