Vitamin Conversion

One of the most common conversion enquiries is about converting between International units (IU) and micrograms (mcg) and milligrams (mg). Commonly, people want to work out the amount of micrograms or milligrams in a medication or vitamin supplement.

What is an International unit?

IU stands for International units and is a unit commonly used in the measurement of medications, vaccines and vitamins. The volume or mass that makes up one International unit is dependent on the concentration or potency of the substance and therefore varies from substance to substance depending on what is being measured. The exact measure of one IU of a substance is in fact established by international agreement for each substance.