Dietary supplement pills containing Vitamin D3. Vitamin D3 (Cholecalciferol) is naturally produced by the body, mainly through exposure to sunlight, and has numerous functions that promote bodily well-being. Proper Vitamin D3 intake enables the absorption of calcium and phosphate in the intestine, thus promoting bone calcification and muscle function. One Vitamin D3 tablet provides a daily dose of 2000 IU (500mcg), which is equal to 1000% of your daily requirement. Taking it is particularly useful for sports activities as it supports: