Vitamin D3, also known as cholecalciferol, is a fat-soluble vitamin that plays a crucial role in maintaining healthy bones and teeth. It helps the body absorb calcium and phosphorus, essential minerals for bone health. The body can produce Vitamin D3 when the skin is exposed to sunlight, making it unique among vitamins. In addition to sunlight, Vitamin D3 can be obtained from certain foods, such as fatty fish, egg yolks, and fortified dairy products. Supplements are also available for those who may not get enough from sunlight or diet. Adequate levels of Vitamin D3 are important for overall health and immune function.