I wonder how much potent version of vitamin d we can obtain from Cholecalciferol (which is usually called vitamin d, which we are buying as a diet supplement). This is a Cholaciferol metabolism: Cholecalciferol---->calcifediol (25-hydroxyvitamin D3)---->calcitriol (1,25-dihydroxyvitamin D3) Calcitrol is the most potent of vitamin d version and is on top end of its synthesis. My question is: If I took once 5000 IU of cholaciferol, how much calcifediol will be made, and how much calcitrol will be made ? How long those 5000IU will be floating in my organism (How long will take to metabolise all cholaciferol to calcitrol)? Please attach some refferences if you can.