Copper tripeptide (GHK Cu; Copper Glycyl histidine tripeptide) CAS 89030 95 5 AbMole BioScience Copper tripeptide Price GHK Cu 50mg Copper Peptide Research Spartan Peptides 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 Reactive oxygen generation by minimal copper binding peptide motifs bioRxiv Cuboctahedral copper cluster promotes main group coordination to new high Research Chemistry World Influence of the counterion on the geometry of Cu(I) and Cu(II) complexes with 1,10 phenanthroline ScienceDirect