Bluebonnet s Vitamin D3 1000 IU Vcaps provide 100% natural vitamin D3 (cholecalciferol) from lanolin in easy-to-swallow vegetable capsules for maximum assimilation and absorption. VitaminsVitamins differ from macronutrients like carbohydrates proteins and fats by virtue of the amount required. Typically minuscule amounts are needed in comparison. Plus vitamins are not used as an energy source.