For the synthetic form of the vitamin, called dl-alpha-tocopherol, the conversion factors are 0.45 and 2.2, respectively. (These conversion factors are for natural vitamin E, which is technically called d-alpha-tocopherol. To convert milligrams of alpha-tocopherol to IUs: multiply the number of milligrams by 1.5. vitamin A in the form of retinol or beta-carotene). Synthetic The recommended daily amount of vitamin E for adults is 15 milligrams a day. Evidence. Many biological agents exist in different forms or preparations (e.g. International units are used to quantify vitamins, hormones, some medications, vaccines, blood products, and similar biologically active substances. Research on vitamin E use for specific conditions shows: Alzheimer's disease. International Units of Vitamin E. The vitamin-E content of a food or recipe is sometimes measured in milligrams of alpha-tocopherol (often written as "a-tocopherol"), and sometimes in International Units (IUs).There is a mathematical relationship between the two measures: one IU … Once you know the equivalents, it's fairly simple to convert IU to mg, then all you need is pen and paper. Vitamin E Natural 1 IU = 0.735 mg d-alpha Tocopheryl Acetate 1 IU = 0.671 mg d-alpha Tocopherol 1 IU = 0.861 mg d-alpha Tocopheryl Succinate. ). Below is a conversion chart which we hope will make things a little clearer! mg IU: International Units; RE: Retinol Equivalents; mg: milligrams; mcg: micrograms Disclaimer: Whilst Robert Forbes & Associates has made every effort to be accurate, errors may appear and are inadvertent.