50g/pk- Vitamin D3,Cholecalciferol,VD3 50g/pk - $59.95 Vitamin D3 (cholecalciferol) is mainly synthesized by the body itself. The skin of the human body contains a kind of cholesterol,which becomes vitamin D3 when exposed to sunlight.So if a child is exposed to direct sunlight for more than 4-6 hours, his or herown vitamin D3 synthesis will be basically satisfied.In addition, vitamin D3 can be derived from animal foods, such as liver,especially fish liver oil, which is extracted from the liver of Marine fish. In general, getting enough vitamin D3 from food alone is not easy, so synthesizing vitamin D3 in the body through sunbathing is a particularly important way. Vitamin D3 is a kind of vitamin. It is one of the essential D vitamins for human body. It is a fat soluble vitamin. Its main function is to promote the absorption of calcium and phosphorus in human body, promote the sound of teeth and facilitate bone development. Adult D3 supplementation can prevent osteoporosis and prevent the loss of calcium. The main function of vitamin D3 is to promote the absorption and synthesis of calcium, which can be conducive to the development of human bones and teeth. Regular vitamin D3 supplementation can prevent osteoporosis and tooth aging. Vitamin D is mainly found in various cereals and high-fat foods. Function 1. Improve the body's absorption of calcium and phosphorus, so that the plasma level of calcium and phosphorus saturation. 2. Promote growth and bone calcification, promote sound teeth; 3. Increased phosphorus absorption through intestinal wall and increased phosphorus reabsorption through renal tubules; 4. Maintain the normal level of citrate in the blood 30 dys money back guarantee. Returned items must be in original condition and packaging. Buyer pays returns shipping. No refunds issued unless items are returned.