Natural Factors SunVitamin D3 - 2500 IU - Provides a convenient, high-potency dose of vitamin D as cholecalciferol to help prevent vitamin D deficiency, and for the development and maintenance of strong bones and teeth. Vitamin D3 is the natural form of this vital nutrient and is most effective at raising blood levels of active vitamin D. Each softgel delivers a single 2500 IU dose of vitamin D3 for convenient maintenance of adequate vitamin D levels in people who are deficient due to a low dietary intake, minimal sun exposure, or inadequate absorption. When combined with an adequate calcium intake, a healthy diet, and regular exercise, vitamin D3 helps reduce the risk of developing the brittle, weak bones of osteoporosis.