Convert between MCG and UI for different vitamins. Manage your vitamin intake effectively with accurate conversions.
| Parameter | Value |
|---|---|
| Vitamin | |
| Micrograms (MCG) | |
| International Units (UI) |
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Learn about the changes in vitamin measurement units and how to convert between micrograms (MCG) and International Units (UI) for various vitamins.
In May 2016, the U.S. Food and Drug Administration (FDA) announced regulations requiring changes to the Supplement Facts label related to units of measure and their conversions. These regulations became mandatory starting in 2020-2021. The table below shows the changes in units of measure for several nutrients:
| Nutrient | New DV Unit | Conversion | Older DV Unit |
|---|---|---|---|
| Vitamin A | μg RAE | 1 IU retinol = 0.3 mcg RAE 1 IU supplemental beta-carotene = 0.3 mcg RAE |
IU |
| Vitamin E | mg alpha-tocopherol | 1 IU (natural) = 0.67 mg Vitamin E 1 IU (synthetic) = 0.45 mg Vitamin E |
IU |
| Vitamin D | μg | 1 IU = 0.025 μg | IU |
| Folate | μg DFE | 1 μg DFE = 1 μg folates 1 μg DFE = 0.6 μg folic acid |
μg |
| Niacin | mg NE | 1 mg NE = 1 mg niacinamide 1 mg NE = 1 mg inositol hexanicotinate 1 mg NE = 1 mg niacin 1 mg NE = 60 mg tryptophan |
mg |
Vitamin A in the diet can come in different forms such as retinol, beta-carotene, alpha-carotene, and beta-cryptoxanthin. Some forms have greater bioavailability than others. Previously, Vitamin A was reported in international units (IU). The new FDA labeling guidelines require reporting Vitamin A in μg RAE (retinol activity equivalent) to account for the differing bioavailability of the forms. Conversion is possible only if the sources of Vitamin A are known. For example, 1 μg RAE = 1 μg retinol and 1 μg RAE = 2 μg supplemental beta-carotene.
Vitamin E content must now be determined based on the source and reported as mg alpha-tocopherol rather than in IU. Vitamin E can come from natural or synthetic forms. Naturally sourced Vitamin E is RRR-alpha-tocopherol (d-alpha-tocopherol), and the synthetic form is all rac-alpha-tocopherol (dl-alpha-tocopherol). One mg Vitamin E (alpha-tocopherol) equals 1 mg RRR-alpha-tocopherol or 2 mg all rac-alpha-tocopherol.
New FDA guidelines require that Vitamin D be reported in μg. Manufacturers may also list the IU amount in parentheses following the amount in μg. The conversion is straightforward: 1 IU = 0.025 μg.
Dietary folate can come in different forms such as naturally occurring folates and synthetic folic acid. Previously, all folates were reported as μg folic acid. The new guidelines require reporting in Dietary Folate Equivalents (DFE), with μg of folic acid in parentheses. Folic acid has greater bioavailability than naturally occurring folates.
Niacin must now be reported as Niacin Equivalents (NE). Dietary niacin can come in several forms, and the new unit accounts for tryptophan as a source of niacin. For example, 1 mg NE = 1 mg niacinamide or 60 mg tryptophan.