endogenous

adjective

en·​dog·​e·​nous en-ˈdä-jə-nəs 

1

: growing or produced by growth from deep tissue

endogenous plant roots

2

a

: caused by factors inside the organism or system

suffered from endogenous depression

endogenous business cycles

b

: produced or synthesized within the organism or system

an endogenous hormone

endogenously adverb

Did you know?

When biologists need to make a distinction between things that are produced within a cell or organ and things that affect it from the outside, they use the terms endogenous and exogenous. It used to be thought, for instance, that mutations in cells always resulted from exogenous causes, until it was discovered that substances in the body, including those called oxidants, could cause them endogenously as well. "Circadian rhythms"—the regular cycles, roughly 24 hours in length, that plants, animals, and humans rely on to regulate their days—are endogenously generated and don't actually depend on the sun for their timing.

Examples of endogenous in a Sentence

Recent Examples on the Web

As Rosas-Vidal hinted at, endogenous cannabinoids or endocannabinoids are produced by the body to activate CB1 (cannabinoid receptor 1) receptors, the receptors that are also responsible for producing the psychoactive effects of cannabis. —Paul McClure 24, New Atlas, 24 May 2025

Function and evolution of specialized endogenous lipids in toothed whales Sara Novak is a science journalist based in South Carolina. —Sara Novak, Discover Magazine, 28 Apr. 2025

That is the type of depression that arises—sometimes quite rationally—from a current set of problems or circumstances, and is different from endogenous, or persistent, free-floating depression. —Jeffrey Kluger, Time, 29 Apr. 2025

Hackman's toxicology test showed acetone levels at 5.3 mg/dl, where as reported normal endogenous acetone levels in blood are up to 0.3 mg/dL. The findings are consistent with a prolonged level of fasting. —Christina Dugan Ramirez , Tracy Wright, FOXNews.com, 27 Apr. 2025

Word History

First Known Use

1830, in the meaning defined at sense 1

Medical Definition

endogenous

adjective

en·​dog·​e·​nous en-ˈdäj-ə-nəs 

variants also endogenic

ˌen-də-ˈjen-ik 

1

: growing from or on the inside

endogenous spores

2

: caused by factors within the body or mind or arising from internal structural or functional causes

endogenous malnutrition

endogenous psychic depression

3

: relating to or produced by metabolic synthesis in the body

endogenous opioids

endogenous amino acids

compare exogenous

endogenously adverb