endorphin
noun
en·dor·phin
en-ˈdȯr-fən 
: any of a group of endogenous peptides (such as enkephalin) found especially in the brain that bind chiefly to opiate receptors and produce some pharmacological effects (such as pain relief) like those of opiates
specifically
: beta-endorphin
Did you know?
The word endorphin was coined, back when the substances were discovered in the 1970s, by joining pieces of endogenous and morphine, morphine being a narcotic that closely resembles the endorphins and relieves pain in a similar way. Studies suggest that the pain-relieving practice called acupuncture works by releasing endorphins. Endorphins also seem to play an important role in pregnancy. Though much remains to be learned about the endorphins, the general public seems ready to give them credit for any all-natural high.
Examples of endorphin in a Sentence
Recent Examples on the Web
Each immersion releases endorphins and serotonin, chemicals that regulate mood and the body’s response to pressure.
—
Samantha Agate, Miami Herald, 30 Apr. 2026
Each session prompts the release of endorphins and serotonin, both of which help regulate mood and how the body responds to pressure.
—Samantha Agate, Charlotte Observer, 30 Apr. 2026
Dopamine and endorphin effects are still being refined in human imaging studies, but cold exposure clearly activates brain systems tied to attention, mood and stress regulation.
—Samantha Agate, Kansas City Star, 30 Apr. 2026
In studies on pain, placebos cause the brain to release endorphins, the body’s natural opioids.
—Phil Starks, The Conversation, 21 Apr. 2026
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Samantha Agate, Miami Herald, 30 Apr. 2026
Each session prompts the release of endorphins and serotonin, both of which help regulate mood and how the body responds to pressure.
—Samantha Agate, Charlotte Observer, 30 Apr. 2026
Dopamine and endorphin effects are still being refined in human imaging studies, but cold exposure clearly activates brain systems tied to attention, mood and stress regulation.
—Samantha Agate, Kansas City Star, 30 Apr. 2026
In studies on pain, placebos cause the brain to release endorphins, the body’s natural opioids.
—Phil Starks, The Conversation, 21 Apr. 2026
See All Example Sentences for endorphin
Cite this Entry
“Endorphin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/endorphin. Accessed 5 May. 2026.
Copy CitationMedical Definition
endorphin
noun
en·dor·phin
en-ˈdȯr-fən
: any of a group of endogenous peptides (as enkephalin and dynorphin) found especially in the brain that bind chiefly to opiate receptors and produce some of the same pharmacological effects (as pain relief) as those of opiates
specifically
: beta-endorphin
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