Vitamin D-3 maintains healthy calcium and phosphorus levels in the body for strong bones, it helps maintain muscle strength in older adults, and it also plays an active role in a healthy immune response. Vitamin D-3 (cholecalciferol) is the optimal form of vitamin D. It is the form of vitamin D that the body manufactures in sunlight, and the form most efficient for the body's needs. Contains no yeast, dairy, egg, gluten, soy or wheat. Contains no preservatives, or artificial color, flavor or fragrance.