Vitamin D is an essential vitamin for overall health and wellness and is especially important for bone density as you age. Our Vitamin D-3 supplement features the most bioactive form of vitamin D for superior absorption. Vitamin D is an essential nutrient for overall health and well-being. Vitamin D is the only vitamin that must be synthesized by the skin from exposure to ultraviolet radiation from sunlight. Due to lack of time in the sun and use of sunscreen, the majority of people in the United States are deficient in Vitamin D. Lack of vitamin D may be linked to various forms of cancer, autoimmunity and other health issues. Our Vitamin D-3 supplement contains cholecalciferol, the natural form of vitamin D.