GHK Cu Topical vs Injection Which is the Better Copper Peptide Form? TJ. Glutathione peroxidase is an important enzyme in cellular antioxidant defense systems, detoxifying peroxides and hydroperoxides. As a component of the glutathione cycle, it protects the liver from reactive oxygen metabolites. Selenocysteine Glutathione redox cycle. Glutathione (GSH) is synthesized from the Download Scientific Diagram GHK Cu HGH & Peptides Deus Medical