D3 dietary supplement contains vitamin D3, which supports the body's immunity and helps maintain healthy teeth and bones1dietary supplement containing vitamin D in the form of cholecalciferol (D3)contains 2000 UI of vitamin D3 in one capsulecontains 1000% of the daily requirement (RWS) for vitamin D3D3 dietary supplement taken regularly:Vitamin D3 helps in the proper functioning of the immune system1vitamin D3 helps maintain healthy bones and teeth1vitamin D3 helps in the proper absorption/utilization of calcium and phosphorus1vitamin D3 helps in the proper functioning of muscles1.