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 Advanced Spectroscopy for Copper Peptide Research Influence of Coordination Geometry upon Copper(II I) Redox Potentials. Physical Parameters for Twelve Copper Tripodal Ligand Complexes Inorganic Chemistry Buy GHK Cu 50mg & 100mg Copper Tripeptide Koi Peptides