There is no definitive answer as to whether retinol vs peptides are better for anti aging. However, there is a lot more research backing retinol as an effective ingredient, while peptides are still Epigenetic mechanisms activated by GHK Cu increase skin collagen density in clinical trial EurekAlert! GHK Cu Topical Sky Blue Cream & Royal Blue Serum Bundle Aseir Custom Skin Perfection GHK Cu Copper Peptide Serum Booster, 1 Percent Blue Liquid For Face, Neck, Body, Hair, And Scalp, 0.5 oz Walmart.com GHK Cu Organic Serum Copper Peptide for Anti Aging & Skin Repair