Dietary Supplement Bonus Size Natural Source Purity & Potency Guaranteed Isura Non-GMO Mass Spec Documentation Lab Tested Vitamin E 400 IU is a high potency, naturally sourced Vitamin E in the form of d-alpha tocopherol with naturally occurring beta-, delta- and gamma-tocopherols. Vitamin E is an antioxidant that protects cell membranes and prevents free radical damage to the body. It supports the cardiovascular system and general health. Daily supplementation of Vitamin E is particularly important for people in polluted environments and those with active lifestyles.