Vitamin D 2000 contains 2000IU of the bioidentical form of vitamin D. Vitamin D is most widely known as the sunshine vitamin because the body is able to make vitamin D when exposed to sunlight. Vitamin D plays an important role in supporting bone health, maintaining cardiovascular function and immune function, and promoting an overall sense of well-being. Vitamin D is available in two different forms, D2 and D3. Vitamin D3 is the preferable form as it has been found to maintain vitamin D levels in the body for a longer period of time when compared to vitamin D2.