International Unit of Vitamin A

**Semantic type:** Quantitative Concept

**Definition:** An arbitrary unit of measurement of the specific biological activity of vitamin A, defined by the International Conference for Unification of Formula as equal approximately to 0.30 micrograms of all-trans retinol or to 0.60 micrograms of the provitamin A, all-trans-beta-carotene.

**Synonyms:** - IU Vitamin A - [iU]{Vitamin A} - [iU]{Vitamin A} - [iU]{Vitamin A}