What Are Endorphins?
Endorphins are morphine-like chemicals produced by the body that help diminish pain while triggering positive feelings.
They’re sometimes referred to as the brain’s “feel-good” chemicals, and are the body’s natural painkillers.
Endorphin is a combination of the words “endogeno” (produced within the body) and “morphine.”
The pituitary gland releases endorphins during periods of strenuous exercise, emotional stress, pain, and orgasm, but also with things like eating, laughing, or getting a massage, according to the Cleveland Clinic.
Endorphins help relieve pain and induce feelings of pleasure or euphoria. They play an important role in the brain’s reward system, which includes activities such as eating, drinking, sex, and maternal behavior.
Some scientists suspect that people with chronic pain conditions, including fibromyalgia and chronic fatigue syndrome, may have lower-than-normal levels of endorphins, although definitive research on this area is lacking.
Narcotic pain medications, including morphine, oxycodone, and codeine, work by mimicking natural endorphins.
Endorphins and Exercise
The body produces endorphins in response to intense physical exercise.
Endorphins may play a role in the so-called “runner’s high,” which describes the feelings of euphoria long-distance runners experience after prolonged bouts of exercise.
Endorphin release varies from person to person, which means that the same amount of exercise does not produce the same amount of endorphins for everyone.
Research suggests that exercise helps to improve mood and may even aid in the treatment of depression.
However, it’s unclear whether endorphins or some other process in the brain or body is responsible for the mood-boosting effects of exercise.
Endorphins and Addiction
Because endorphins play a role in the brain’s reward system, some scientists and doctors have suggested that these natural chemicals may play a role in exercise addiction or drug dependence.
Exercise addiction may occur in people who exercise excessively. It’s characterized by symptoms of withdrawal, such as feeling depressed, anxious, restless, or guilty after not exercising.
But few scientific studies have evaluated the link between increased endorphin levels, vigorous exercise, and dependence or addiction.

Heidi Green, MD
Medical Reviewer

Lindsey Konkel
Author
Lindsey Konkel is an award-winning freelance journalist with more than 10 years of experience covering health, science, and the environment. Her work has appeared online and in pri...
- Endorphins. Cleveland Clinic. May 19, 2022.
- Pain. National Institute of Neurological Disorders and Stroke. July 11, 2023.
- Boecker H, Sprenger T, Spilker ME, et al. The Runner’s High: Opioidergic Mechanisms in the Human Brain. Cerebral Cortex. November 2008.