IU to mg
In pharmacology, the International Unit is a unit of measurement for the amount of a substance, based on measured biological activity or effect. "International Unit" is abbreviated as IU. It is an old measurement of vitamin activity determined by biological methods as opposed to new measures that are determined by direct chemical analysis.
Many health foods and supplements still use i.u. ( IU ).
For Vitamin A, 1 i.u. = 0.3µg retinol, 3.6µg b-carotene, or 7.2µg other vitamin A carotenoids
For Vitamin D, 1 i.u. = 0.025µg cholecalciferol
For Vitamin E, 1 i.u. = 0.67µg natural a-tocopherol (different conversion factors are used for different forms of vitamin E)