Active form and high absorption. Cholecalciferol is the active form of Vitamin D3, so it provides superior absorption compared to regular Vitamin D3. When taken directly in this format it works more quickly and can be delivered in lower concentrations. Vitamin D3 in liquid-filled hard shell capsule form is easy to swallow and convenient to take. Some research indicates that vitamin D3 in liquid-filled capsule form is more highly bioavailable than in powdered or tablet forms. Activates the immune system.