Thermodynamically stable ionic liquid microemulsions pioneer pathways for topical delivery and peptide application ScienceDirect 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 Amazon.com: Skin Perfection Copper Peptide Serum GHK CU 1% for Face & Hair Copper Peptides for Skin, Hair, & Scalp 1% Blue Liquid for Face, Neck, Body, Scalp Multi Use Serum Booster with Blue Me Away: Skin Biology 7% GHK Cu Accelerant Review BeautyandtheCat's Beauty Blog Can You Use GHK Cu Peptides with Vitamin C Serum? Expert Guide