Get 5,000 IU of vitamin D3 (as cholecalciferol) with each softgel of Life Extension Vitamin D3. Vitamin D is the latest fundamental nutrient to receive attention from researchers and health professionals. This new data has led many doctors, health associations and concerned scientists to call for daily supplementation by every adult, especially during winter months for those living at great distances from the equator where there are limited daylight hours to provide for natural production. Vitamin D3 benefits include support for healthy bones, immune system function and more.