GHK Cu 50 mg Copper Peptide Research Grade PRG GHK Cu 100mg Research Compound Australia Buy GHK Cu Exceptional 99%+ Purity Third Party COA Included 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 Buy GHK Cu Exceptional 99%+ Purity Third Party COA Included Theoretical study of copper binding to GHK peptide ScienceDirect