We are offering calcitriol. Calcitriol also called 1, 25-dihydroxycholecalciferol or 1, 25-dihydroxyvitamin d3, is the hormonally active form of vitamin d with three hydroxyl groups (abbreviated 1, 25-(oh)2d3 or simply 1, 25(oh)2d), it increases the level of calcium (ca2+) in the blood by (1) increasing the uptake of calcium from the gut into the blood, and (2) possibly increasing the release of calcium into the blood from bone.