<prompt> Most active form of vitamin DCalcefedialCalcitriol7-dehydrocholecalciferalVitamin D3  <response>: Vitamin D- is a fat-soluble vitamin, chemically related to the steroids and essential for the normal formation of bones and teeth and for the absorption of calcium and phosphorus from the GI tract.1a,25-Dihydroxycholecalciferol or 1,3,25-triol; or calcitriol is the active form of vitamin D, it is more potent than calcidiol. Ref: Ganong;s review of medical physiology;24th edition; page no-379 