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 Copper Peptide: Uncover Its Full Potential New Biotinylated GHK and Related Copper(II) Complex: Antioxidant and Antiglycant Properties In Vitro against Neurodegenerative Disorders China Copper Peptide(GHK Cu) CAS:89030 95 5 Manufacturers Free Sample Alfa Chemical Halogen driven modulation of coordination geometry and electronic properties in copper complexes: Insights from comprehensive structural and computational studies ScienceDirect