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 tripeptide (GHK Cu; Copper Glycyl histidine tripeptide) CAS 89030 95 5 AbMole BioScience Copper tripeptide Price Copper Peptide GHK Cu for Sale Stanford Advanced Materials Aqueous Solution Equilibria and Spectral Features of Copper Complexes with Tripeptides Containing Glycine or Sarcosine and Leucine or Phenylalanine