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 (50mg) Nordsci Cuboctahedral copper cluster promotes main group coordination to new high Research Chemistry World GHK Cu 50mg Copper Peptide Research Spartan Peptides Copperbiomolecule complexes in the gas phase. The ternary way Tureek 2007 Mass Spectrometry Reviews Wiley Online Library