Is Less More? Influence of the Coordination Geometry of Copper(II) Picolinate Chelate Complexes on Metabolic Stability Inorganic Chemistry 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 Halogen driven modulation of coordination geometry and electronic properties in copper complexes: Insights from comprehensive structural and computational studies ScienceDirect