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 Optimal Glutathione IV Dosage & Detox Benefits in Los Angeles FDA highlights concerns with using dietary ingredient glutathione to compound sterile injectables FDA Copper Peptides GHK Cu Beef Tallow for Skin: Blue Balm with Methylene Blue, Manuka Honey & Vitamin E Natural Face and Body Moisturizer for Mature, Dry & Sensitive Skin 2oz