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 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 GHK CU (50mg) Nordsci Buy GHK Cu Exceptional 99%+ Purity Third Party COA Included What is GHK Cu Collagen and Elastin Support Neurogan Health Theoretical study of copper binding to GHK peptide ScienceDirect