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 FDA Peptide Reclassification 2026 Amanecia Health GHK CU Crescent Chems Research Blue Copper Peptide Ghk Cu 99% Care Ghk Cu 50mg 100mg vials Cosmetic Ingredient GHK GHK CU and blue copper GHK CU 1 gram FITSKNS Peptides