Vitamin D3 (Cholecalciferol) 1000 IU (25 mcg) is a premium formula delivering vitamin D in the form that is easiest to use by the body - D3. Supporting optimal wellbeing, the benefits of the \"sunshine vitamin\" are numerous and well documented, but particularly for immune health. Vitamin D is a fat-soluble vitamin that is required to promote calcium absorption, which helps to maintain healthy bones and teeth. Solgar\'s Vitamin D3 is a highly absorbable vitamin D. Obtained from the sunlight or vitamin D rich foods - over a billion people worldwide have very low levels of vitamin D. In addition to changing your diet and lifestyle, taking a vitamin D supplement is a good way to top up, especially in winter months. Vitamin D contributes to: Normal function of the immune system Maintenance of normal bones and teeth Normal absorption of calcium and phosphorus Normal blood calcium levels Maintenance of normal muscle function