GHK Cu: My secret weapon for skin, hair, and healing, I use it two ways topical cream for my face, and subQ injections 3x a week., It boosts collagen, tightens skin, helps hair grow, and even GHK Cu Research Overview Copper Peptide Studies 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 Peptide Regenerative & Cosmetic Research