Douglas Laboratories S.O.D is a dietary supplement for antioxidant support. Superoxide dismutase (SOD) is an antioxidant found in two forms. One is complexed with zinc and copper and localized in the cytosol. The other is bound with manganese and found in the mitochondrial matrix. Both catalyze the inactivation of destructive reactive oxygen species (peroxides) by converting them to hydrogen peroxide which is transformed into water and oxygen by the enzyme catalase. The body's cells and tissues are constantly facing damage from toxic free radicals and reactive oxygen species produced during normal oxygen metabolism. Recommended use: Take 1 capsule daily or as directed by a healthcare professional.