Selenium is an essential trace mineral and functions as part of the antioxidant enzyme glutathione perioxidase. It is bonded to the essential sulfur amino acid, methionine, in a naturally occuring form as found in the diet. Selenium can help form selenoproteins, which have a role in regulating inflammation and immune resonses. Our NOW natural and organic Supplements are an effective way to ensure you and your loved ones are getting essential vitamins, minerals and nutrients for daily optimal health. Since 1968, NOW has been making top quality products that are tested to the highest standards to empower people to lead healthier lives. Our promise - what is on the label, is precisely what is in the bottle.