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 Two Weeks on GHK CU by Rory Uphold The Ladies Room GHK CU 100MG MOB Biotech 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