GHK Cu is a naturally occurring tripeptide in human plasma. Levels average 200 ng ml at age 20 and drop to 80 ng ml by age 60 (Pickart et al., 2020). That decline tracks with Copper peptides like GHK Cu work by sending signals to your skin to repair, regenerate, and produce collagen. It's not about instant results, it's about improving how your skin functions over time. Dr. Amazon.com: Copper Peptides Serum for Face Peptides Collagen Renewal & Anti Aging Serum GHK Cu, EGF, Hyaluronic Acid,Collagen Anti Wrinkle, Firming, Moisturizing Korean Skin Care,25mL 0.88 Fl Oz : Beauty & Personal Care GHK Cu Copper Peptide: Dosage, Before and After Results, and How It Works Perfect B