Vitamin D3 is officially known as cholecalciferol, nicknamed the "sunshine Vitamin," Offering insight into one of the ways humans can get the vitamin. Aside from exposure to sunlight, you can also obtain Vitamin D3 by eating certain foods, such as fish, eggs, and milk fortified with the vitamin. However, many people do not have adequate levels of Vitamin D3 in their system and therefore require supplements. Vitamin D3 is a crucial nutrient for overall health. However even though the body is capable of manufacturing Vitamin D3 from the UVB rays of sunlight, millions of individuals are deficient in this life-sustaining bone building, and immune modulating vitamin. Zahler's D3 provides supplemental doses of this critical vitamin, promoting healthier bodies.