Buy GHK Cu Peptide 99%+ Purity GHK Cu for Research 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 Is Less More? Influence of the Coordination Geometry of Copper(II) Picolinate Chelate Complexes on Metabolic Stability Inorganic Chemistry Is Less More? Influence of the Coordination Geometry of Copper(II) Picolinate Chelate Complexes on Metabolic Stability Inorganic Chemistry Influence of Coordination Geometry upon Copper(II I) Redox Potentials. Physical Parameters for Twelve Copper Tripodal Ligand Complexes Inorganic Chemistry