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 Halogen driven modulation of coordination geometry and electronic properties in copper complexes: Insights from comprehensive structural and computational studies ScienceDirect Copper Tripeptide (GHK Cu) for Advanced Skincare & Haircare Formulatio GHK Cu may Prevent Oxidative Stress in Skin by Regulating Copper and Modifying Expression of Numerous Antioxidant Genes