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 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 Gray Market Peptides Etsy Wellness peptide craze: why people are injecting drugs 'not for human consumption' Grey market peptides: what pharmacists need to know The Pharmacist