Used as a measure of comparative potency of natural substances, such as vitamins, before they were obtained in a sufficiently pure form to measure by weight.
An international standard of the biological effects of a particular amount of a substance, e.g., vitamin.
An internationally agreed standard used in pharmacy as a measure of a substance such as a drug or hormone.
Units for measurement of the biological potency of several vitamins, for example, vitamin A, on an agreed International basis; the present tendency is to avoid such arbitrary units, and use ordinary units of mass (milligram or microgram).
A system that standardizes measures of weight and volume in countries throughout the world.
An internationally accepted amount of a substance. Usually this form of expressing quantity is used for fat-soluble vitamins and some hormones, enzymes, and biologicals such as vaccines. These units are defined by the International Conference for Unification of Formulae.
A standard measurement of an antibiotic, vitamin, enzyme, or hormone, the amount of which produces a specific biological result.
A universally accepted benchmark that measures the functional potency of a specific biological element, like a vitamin.