Incorporate GHK Cu LS5 Copper Serum in Your Skincare Routine Retinoids vs Peptides (Matrixyl CP): what to pick + how to pair, Effectiveness: Retinoids (retinol tretinoin) have the strongest clinical data for photoaging (wrinkles, texture, tone). Peptides Peptides vs. Retinol Which is Better For Skin Health? 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 Copper Peptides vs. Retinol & Vitamin C: What to Choose? by DrBeautiology Medium Copper Peptides for Skin: What GHK Cu Does and How It Compares to Retinol