Copper peptide GHK-Cu is a complex of metal copper ions and tripeptides. Due to its rich content of non-ferrous metal copper ions, blue copper peptide presents a unique and elegant blue color. It is the earliest discovered peptide with beauty effects.

Relevant literature believes that in order to exert the efficacy of the copper peptide GHK-Cu, the coordination state of copper ions and tripeptide must be maintained, but acidic substances can easily free the copper ions in the complex, which will reduce the activity of superoxide dismutase and thus reduce the antioxidant effect.