Rigid flexible nanocarriers loaded with active peptides for antioxidant and anti inflammatory applications in skin ScienceDirect 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 100mg Rigenerazione e antiossidante 070 000 251 Copper Peptide GHK Cu, CAS 49557 75 7