Uni-Pharma D3 Fix Extra 2000 IU 60tabs Vitamin D3 is produced by the photolytic action of ultraviolet radiation on the skin. Despite the fact that every organism can produce vitamin D3 , the modern lifestyle and insufficient exposure to sunlight results in a deficiency of vitamin D3 , which must necessarily be obtained through food, as its role in maintaining the body in good condition is important. Vitamin D3 has an essential role in maintaining calcium and phosphorus homeostasis and, consequently, in maintaining bone and tooth health. In addition, vitamin D3 is involved in tissue metabolism and its presence in sufficient quantities is essential for cell differentiation and maintaining membrane functionality, as well as for the function of various organs such as the skin, muscles, pancreas, nerves, parathyroid gland and the immune system.