Vitamin D is a fat-soluble vitamin that can be obtained through the diet or synthesized in the skin upon exposure to sunlight. Vitamin D3, the form of vitamin D formed in the skin, is a potent and active form of the vitamin. Vitamin D2 is a vitamin D analog formed in plants, mushrooms and yeasts during photosynthesis. While vitamin D2 is sometimes used in food fortification, Puritan’s Pride supplements provide the active form.

Vitamin D plays a regulatory role in the growth, differentiation, and proliferation of different types of white blood cells.8*