A GHK Cu face serum appears blue because the active ingredient, GHK Cu (copper peptide), is naturally a blue colored powder, meaning its inherent color transfers to the serum when mixed in; this blue hue Copper Peptide Serum for Dull & Mature Skin VALNCIA 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 Glutathione Deficiency Symptoms: Is Poor Sleep Just the Beginning? Cardiology & Neurology Specialists located in Queens, Forest Hills and Brighton Beach, Brooklyn, NY Advanced Medical Care