Ideos 500 mg / 400 IU is indicated in the elderly, in cases of calcium and vitamin D deficiency and in people being treated for osteoporosis (a bone disease where the bone becomes less dense and becomes brittle) to supplement calcium and vitamin D deficiency. Ideos 500 mg / 400 IU contains 500 mg of calcium per tablet, i.e. 1250 mg of calcium carbonate, 400 IU of cholecalciferol (vitamin D3) or 4 mg of cholecalciferol concentrate (powdered form).