Tag: Medical units

An International Unit (IU) of Vitamin D is equivalent to 0.025 micrograms, while an enzyme unit (U) for a different substance has no comparable mass-based value. This fundamental distinction highlights why understanding the difference between U and IU is vital in medical contexts and supplementation.

The International Unit (IU) is a measure of biological activity, not a fixed weight, which means there is no single, universal conversion for how much is IU in ng. This conversion factor varies dramatically depending on the specific substance, such as vitamins, hormones, or other biological compounds. For example, the conversion for Vitamin A is different from Vitamin D, making it crucial to know the substance you are measuring.