Copper peptide GHK Cu Tripeptide Proteasome Bortezomib, angle, white png PNGEgg 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 Aqueous Solution Equilibria and Spectral Features of Copper Complexes with Tripeptides Containing Glycine or Sarcosine and Leucine or Phenylalanine Ghk Cu Copper Peptide: Uncover Its Full Potential Theoretical study of copper binding to GHK peptide ScienceDirect