Copper peptide (GHK Cu) SIELC Technologies COPPER TRIPEPTIDE GHK AGE REGRESSION.COM 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 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