Buy GHK Cu Peptide 99%+ Purity GHK Cu for Research Theoretical study of copper binding to GHK peptide ScienceDirect 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 Molecular crystal structure of the tripeptide GHK Cu. In solution, Download Scientific Diagram N2 (N Glycyl L histidyl) L lysinato(2 )]copper 89030 95 5 wiki