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 50 mg Copper Peptide Research Grade PRG Aqueous Solution Equilibria and Spectral Features of Copper Complexes with Tripeptides Containing Glycine or Sarcosine and Leucine or Phenylalanine GHK Cu Copper Peptide: The Complete Research Guide CertaPeptides Copper peptide (GHK Cu) SIELC Technologies