In our supplements, 500 mcg of whole food Beta carotene is approximately equivalent to 1,000 IU (International Units) of Vitamin A or 300 mcg RAE (Retinol Activity Equivalents). RAE is a standardised measurement that factors in the differing bioactivities of retinol and provitamin A carotenoids, like Beta-carotene. This conversion allows your body to safely and effectively get the Vitamin A it needs.