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 Best Glutathione Supplement 4 Recommendations in 2026 GHK CU (Copper Peptide Serum) NovaNAD+ 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 Buy GHK Cu Cream 0.5% Copper Peptide Pure, Potent, USA Made