exogenous
adj.adj. coming from outside a system or organism. In medicine, it describes things like drugs that enter the body from the outside.
adj. originating or produced from an external source. In pharmacology, it refers to substances that are administered from outside the body, as opposed to being produced internally.
The doctor explained that the medicine is exogenous.
The patient's symptoms were caused by an exogenous substance rather than a problem with their own body chemistry.
While the body can produce certain hormones internally, exogenous sources like dietary supplements or synthetic medications are often required to maintain specific therapeutic levels in the bloodstream.
From exo- + -genous.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Last updated May 30, 2026