GHK Cu Say hello to your skin's new BFF GHK Cu is a powerful peptide that supports collagen production, speeds healing, improves hair growth, and helps fight visible signs of aging. This tiny molecule NL GHK Cu (TETRAPEPTIDE + CU) Synthagen Synthagen PL GUYWL Copper Peptide Cream with 2% * & 5% Niacinamide Hydrates * and Smoothes Skin for * in a Uniform Light Beige Tint, Suitable for Face and Neck an Ideal Gift for Holidays, Birthdays. Scientists sum up the evidenceor lack thereoffor the most popular peptides hyped for athletic performance and recovery.