How to Use GHK Cu Repairing Serum SumaNurica Your copper peptide product should be this exact blue. If it isn't, you already have your answer. GHK Cu is blue because of coordination chemistry, not dye. The Cu ion at the center Copper Peptide Body Wash Anti Aging, Skin Firming & Hydration Pept Peptide Labz MOUNTAINOR Liposomal Glutathione Tablets for Glowing, Whitening & Brightening Clear Skin with Vit C