Today we are talking about vitamin D. Vitamin D is a fat-soluble vitamin. It is a group of generic sterol derivatives with anti-rickets effect and similar structure. The most important ones are vitamin D3 (cholecalciferol, cholecalciferol) and vitamin D2 (calciferol). The main function of vitamin D is to promote the absorption of calcium and phosphorus by small intestinal mucosal cells. Vitamin D also promotes skin cell growth, differentiation and regulates immune function. The average adult is often exposed to sunlight to prevent deficiency. Infants, pregnant women, nursing mothers, and elderly people who do not frequently go outdoors should increase the vitamin D supply to 10 μg per day (equivalent to 400 international units). Children lacking vitamin D can suffer from rickets and adults suffering from osteomalacia. This shows that vitamin D supplementation is very important. Calcium plus vitamin D3 soft capsules, calcium plus vitamin D chewable tablets, and vitamin A plus D soft capsules produced by Guangzhou Changsheng Kang Biotechnology Co., Ltd. can all well meet the vitamin D we need to supplement every day.