GHK Cu Copper Peptide 50mg Cypress Compound Co 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 Coordination Compounds as Biologically Active Agents GHK Cu C28H48CuN12O8 CID 133697840 PubChem Molecular crystal structure of the tripeptide GHK Cu. In solution, Download Scientific Diagram Advanced Spectroscopy for Copper Peptide Research