Vitamin D2 is also known as ergocalciferol. The molecular formula is C28H44O. It is a fat soluble vitamin that helps the body absorb and metabolize calcium and phosphorus. It helps the body accomplish this by increasing the efficiency of the small intestine to absorb these minerals from the diet.
Vitamin D2 is converted to 25-hydroxyvitamin D [25(OH)D] in the liver, and then to the active form, 1,25-dihydroxyvitamin D [1,25(OH)2D], in the kidney. Once transformed, it binds to the vitamin D receptor, which leads to a variety of regulatory roles, such as calcium and phosphorus balance.