High Potency Cholecalciferol Vitamin D3 (cholecalciferol) is readily converted in the body to a hormone that helps manage calcium, and is important for the brain, the heart, circulation and healthy immune functioning in addition to bone, muscle, lung, joint and kidney health. Vitamin D3 is a component of the comprehensive brain program developed by leading clinical neuroscientist Daniel Amen, MD. Promotes healthy mood management. Supports healthy circulation and blood flow to the brain. Important for early brain development and adult brain health.