GHK Cu vs NAD+: Which Longevity Peptide Should You Take or Stack? Get glowing skin with GHK CU peptide therapy GHK CU is a naturally occurring plasma peptide that significantly declines during aging. GHK CU exhibits anti aging properties by: stimulating collagen production improving skin elasticity and Glow Peptide Injection: Revolutionizing Skin Rejuvenation Hubmed GHK Cu may Prevent Oxidative Stress in Skin by Regulating Copper and Modifying Expression of Numerous Antioxidant Genes