1% GHK CU solution: is this applied directly on skin or diluted further? : r DIYaesthetics A GHK CU Blue Copper Peptide Serum Concentrate Ampoule Anti Wrinkle Firming Moisturizing Elasticity Acne Treatment Skincare Alibaba.com Understanding Glutathione Deficiency Invigor Medical 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