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 50mg 10mL Vial: Automatic Refills Celia Health Amazon.com: Skin Perfection GHK Cu Copper Peptide Powder 99.7% Pure DIY Copper Peptides Serum for Face and Scalp Cosmetic Grade GHK Cu 1 Gram Creates Up to 100ml for Fuller Hair and GHK CU: How to Mix It The Peptide Report