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: Dosage, Before and After Results, and How It Works Perfect B Don't Be Fooled by Color: Choosing the Right GHK Cu Copper Peptide Serum Peptide Labz The Ultimate L Glutathione Supplement Guide 2022: Uses, Benefits, Side Effects & Dosing Skin Perfection GHK Cu Copper Peptide Serum Booster, 1 Percent Blue Liquid For Face, Neck, Body, Hair, And Scalp, 0.5 oz Walmart.com