Not all Copper Peptides are created equal If you've tried copper peptides before and saw no change, here is why: Concentration and Stability. Most serums use a diluted solution that barely scratches GHK Cu: The Peptide That Transforms Skin and Tissue Health Calibrate Hydration Hyaluronic Acid 2% + GHK Cu (Serum) G Lab Peptides GHK Cu Copper tripeptide (1% solution) Sapolita Squalane + Copper Peptide (GHK Cu) Rapid Plumping Serum