Frontiers Exploring the beneficial effects of GHK Cu on an experimental model of colitis and the underlying mechanisms 89030 95 5 GHK Cu Gly His Lys Cu Copper Tripeptide 1; Prezatide copper 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 peptide(GHK Cu) TFA salt 89030 95 5 FC138108