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 GHK Cu as a multifunctional copper peptide: synthesis routes, process engineering and emerging applications Systems Microbiology and Biomanufacturing Springer Nature Link Theoretical study of copper binding to GHK peptide ScienceDirect Copper Peptide (GHK Cu) Supplier Cosmetic Ingredient for Formulators Creative Peptides Buy GHK Cu 50mg, 75mg, 100mg Peptides.GG