Benefits of NutraBio Vitamin D (5000 IU) Contributes to bone strength and bone formation* Supports proper functioning of the immune and nervous systems* Promotes the intestinal absorption of calcium* Supports fetal skeletal development and tooth enamel formation* Contributes to healthy levels of phosphorus in the body* Vitamin D3 (as cholecalciferol) is a fat-soluble vitamin that's naturally present in very few food sources. It has many functions in the body from contributing to bone health to supporting immune function. NutraBio Vitamin D3 is the same form of Vitamin D3 the body manufactures when skin is exposed to ultraviolet (UV) sunlight. Vitamin D3 may be more than three times as effective than other forms of Vitamin D3 in raising concentrations in the bloodstream and maintaining those levels for a longer time.*