Selenium is an essential trace mineral that inhibits the oxidation of lipids (fats) and works synergistically with vitamin E to assist in the production of antibodies and maintain a healthy liver, pancreas, thyroid, and heart function.

Recently, selenium as selenocysteine has been identified in the active center of type 1 and 3 iodothyronine deiodinases, two important enzymes regulating the formation and degradation of the active thyroid hormone, triiodothyronine (T3). Incomplete conversion of T4 to T3 can lead to hypothyroid symptoms.

Selenium also protects the thyroid from attacking antibodies. Selenium also serves as an antioxidant by activating glutathione peroxidase, an antioxidant enzyme that protects cells from reactive oxygen metabolites by removing the reactants, water, and oxygen. Unlike inorganic forms of selenium, Seleno-Methionine is not adversely affected by vitamin C.