People who live far away from the equator may not make enough Vitamin D in their skin during long, gloomy winters. This vitamin is essential for bone development and is needed for calcium and vitamin C absorption and supports the nervous system. Vitamin D3, which is the same form found in fish oils and eggs, is the form produced by sunlight on human skin.
Natural Factors Vitamin D3 (cholecalciferol) is derived from sheep wool lanolin. Vitamin D contributes to the maintenace of normal bones, teeth and muscule function and the immune system