Endogenous Substance and Your Body

Endogenous means caused by factors or produced inside an organism or cell. An endogenous human substance, therefore, is a substance that originates within the human body.

Endogenous is the opposite of exogenous, which means originating outside a living organism. Some exogenous substances are harmful, while others are used as medications or supplements to imitate or counteract the action of endogenous substances. This is a common method of disease treatment.

This article describes some common endogenous substances, some of which also have exogenous counterparts.

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Examples of Endogenous Substances

Here are several examples of endogenous substances:

Endogenous Cholesterol

The two sources of cholesterol are: dietary cholesterol and cholesterol originating in your own body. Endogenous cholesterol is produced by your own liver inside your body, and exogenous cholesterol comes from the food you eat.

While endogenous and exogenous cholesterol can both be beneficial—these substances can be harmful if you consume too much or if your body makes too much.

Endogenous Opioids

Your body can manufacture its own pain relief in the form of endogenous opioid compounds. In fact, your brain actually activates these self-manufactured drugs to prevent pain in certain cases—this is the physical mechanism behind the "runner's high."

Opioid medications work similarly, by blocking pain receptors. However, opioid medication dosing is tricky, and the side effects can be dangerous. Side effects are not a problem with endogenous opioids.

Endogenous Autoantibodies

Your immune system is designed to fight against foreign invaders like viruses and bacteria. Sometimes, though, the immune system makes antibodies that mistakenly attack a person's own organs and other tissues.

These endogenous autoantibodies originate within the body and are called "auto" antibodies because they're attacking their own organism. People who have this type of immune malfunction can develop autoimmune diseases such as celiac disease (where the endogenous autoantibodies attack the small intestine) or type 1 diabetes (where they attack the pancreas).

For some autoimmune conditions, like rheumatoid arthritis, anti-inflammatory medications that dampen the endogenous immune system function can alleviate symptoms. But in other autoimmune diseases, like celiac disease and diabetes type 1, inflammatory suppression won't help because the immune system actually damages tissue. Other treatments, like dietary modification for celiac disease or insulin for diabetes, are needed instead.

Endogenous Hydrogen Sulfide

Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airway obstruction. Put simply, the disease makes it harder and harder to breathe. It is usually due to significant exposure to exogenous noxious particles or gases (like cigarette smoke) but is also influenced by factors internal to one's body.

Medical researchers have investigated what triggers this problem, and have pinpointed several potential culprits. One of these is endogenous hydrogen sulfide. This irritant material is present in the environment, and your body can make it too.

A Word From Verywell

You may frequently hear the names of exogenous substances that also have endogenous forms. Normally, your body does a pretty good job of balancing out different endogenous functions and substances, and sometimes outside interventions are needed to help.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Cancer Institute. NCI Dictionary of Cancer Terms: Endogenous. National Cancer Institute.

  2. Corliss J. How it’s made: Cholesterol production in your body. Harvard Health.

  3. Liao YX, Wang XH, Bai Y, Lin F, Li MX, Mi WJ, Sun WL, Chen YH. Relationship between endogenous hydrogen sulfide and pulmonary vascular indexes on high resolution computed tomography in patients with chronic obstructive pulmonary disease. Int J Chron Obstruct Pulmon Dis. 2021 Aug 10;16:2279-2289. doi:10.2147/COPD.S314349

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