All Puritans Pride Vitamin D formulas are Sunvite D3, a more potent and active form of Vitamin D. Together with Calcium, Vitamin D helps develop strong bones and teeth, and also assists in immune system health. A review study on the benefits of Vitamin D recommends increased use of supplements in the U.S. to help ensure optimal health, and that supplementing with 1000 IU of Vitamin D3 can be an effective way to accomplish this. These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease. As we age, the skin produces vitamin D less efficiently.