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Model o the antioxidant metabolite glutathione. The yellae sphere is the redox-active sulfur atom that provides antioxidant activity, while the reid, blue, white, an dark grey spheres represent oxygen, nitrogen, hydrogen, an carbon atoms, respectively.

An antioxidant is a molecule that inhibits the oxidation o ither molecules. Oxidation is a chemical reaction that can produce free radicals, leadin tae cheen reactions that mey damage cells.