GHK Cu Copper Peptide Cream (Prescription) UluRx 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 GHK Cu Copper Peptide Powder Megan's Miracle GHK CU Snap 8 topical mixing protocol : r DIYaesthetics