is iu the same as micrograms?
In the metric system, 1000 milligrams (mg) is a unit of mass equal to 1 gram and 1000 micrograms (mcg) is equal to 1 milligram (mg). ... Vitamin A: 1 IU is the biological equivalent of 0.3 mcg retinol, or of 0.6 mcg beta-carotene. Vitamin D: 1 IU is the biological equivalent of 0.025 mcg cholecalciferol or ergocalciferol.