Vitamin D3 is an essential fat-soluble vitamin found in certain foods & produced by the body when exposed to sunlight. It's a critical nutrient required to keep your body functioning properly. Taking a vitamin D supplement can promote calcium absorption, facilitating the development & maintenance of strong bones & teeth. It also supports muscle function, immune system modulation, hormone regulation, gene expression, & overall cellular health. Vitamin D3 has been shown to be the most potent & easily absorbed form of vitamin D.