Vitamin D covers two main forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D3 is only found in animal-sourced foods, whereas D2 mainly comes from plant sources and fortified foods. Vitamin D is a fat-soluble vitamin that helps your body absorb calcium and phosphorus. As the manufacturer and supplier of vitamin D2, Ours conforms to USP and EP.