Superoxide Dismutase is an enzyme your body already makes. It breaks down superoxide free radicals, a type of reactive oxygen molecule. Supplements are promoted for joints and skin, though we have little human data on whether swallowed forms actually work that way.
Your gut destroys most unprotected SOD. Manufacturers bond it to gliadin, a wheat protein, to shepherd it through digestion and into the bloodstream. Dose amounts are all over the map because no standard exists.
Safety information is thin. If you have celiac disease or a gluten sensitivity, read the label carefully. Many forms pull gliadin from wheat. No known drug interactions are recorded.