Coordination geometry of the copper(II) peptide core obtained by QM MM Download Scientific Diagram GHK Cu Copper Tripeptide 1 Research Reagent 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 Theoretical study of copper binding to GHK peptide ScienceDirect Theoretical study of copper binding to GHK peptide ScienceDirect Is Less More? Influence of the Coordination Geometry of Copper(II) Picolinate Chelate Complexes on Metabolic Stability Inorganic Chemistry