Selenium is a nutrient found in the body, important for cellular health and building antioxidant defense enzymes. Selenium is also a cofactor for the production of glutathione perioxidase, a vital antioxidant for eye lens health. Selenium can be found naturally in foods like seafood, meats, poultry and dairy products, as well as breads, cereals and grains. You can find a selenium vitamin in multivitamins or as a stand-alone selenium supplement. GNC offers a variety of selenium containing supplements – look to GNC for the best selenium supplement to suit your needs and preferences.