endorphin
Americannoun
-
endorphins
plural
noun
Closer Look
Endorphins are long chains of amino acids, or polypeptides, that are able to bind to the neuroreceptors in the brain and are capable of relieving pain in a manner similar to that of morphine. There are three major types of endorphins: beta-endorphins are found almost entirely in the pituitary gland, while enkephalins and dynorphins are both distributed throughout the nervous system. Scientists had suspected that analgesic opiates, such as morphine and heroin, worked effectively against pain because the body had receptors that were activated by such drugs. They reasoned that these receptors probably existed because the body itself had natural painkilling compounds that also bonded to those receptors. When scientists in the 1970s isolated a biochemical from a pituitary gland hormone that showed analgesic properties, Choh Li, a chemist from Berkeley, California, named it endorphin, meaning “the morphine within.” Besides behaving as a pain reducer, endorphins are also thought to be connected to euphoric feelings, appetite modulation, and the release of sex hormones. Prolonged, continuous exercise contributes to an increased production of endorphins and, in some people, the subsequent “runner's high.”
Other Word Forms
Noun Inflected Forms
Etymology
Origin of endorphin
1970–75; end(ogenous) (m)orphine, with -ine respelled as -in 2
Explanation
If you’re getting sore and tired while running, don’t worry! Just wait for your endorphins to kick in. An endorphin is a hormone that your body produces to ease pain and make you feel calm and happy. Endorphins are sometimes called "natural pain killers," since that's the way they act in the body. Things like stress and exercise can stimulate the release of endorphins. A “runner’s high” happens when a runner gets a rush of endorphins. Your nervous system and pituitary gland send endorphins to your brain, where they bind to special receptors. It's similar to what happens when you take a painkilling medication. In fact, the word endorphin is a blend of “endogenous” (meaning "inside the body") and “morphine" (a medication that relieves pain).
Vocabulary lists containing endorphin
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
“It’s the most effortless thing. It makes us very happy when we get together. There’s an endorphin thing going on.”
From Los Angeles Times ● Aug. 4, 2026
It may be a thrill show and a shallow endorphin rush, but the one thing that it isn’t is journalism, which we still happily criticize.
From Salon ● Feb. 6, 2026
Ubl spent 10 hours a day on his vacation building new software and said each run gave him an endorphin rush akin to playing a Vegas slot machine.
From The Wall Street Journal ● Jan. 17, 2026
Gen Z and millennials are increasingly trading late alcohol-fuelled nights for early-morning endorphin highs to take part in run clubs and earn virtual kudos on fitness apps like Strava.
From BBC ● May 2, 2025
I woke disoriented and crabby, without my customary morning jolt of endorphin.
From Down and Out in the Magic Kingdom by Cory Doctorow
"Of course, our happy chemicals are released too -- endorphins -- and that's what makes us feel more energised and motivated," she said after her game, which was enthusiastically cheered on from the sidelines.
From Barron's ● Jun. 15, 2026
Researchers in the late 1970s found that after patients had their molars extracted, an IV saline drip provided pain relief through the body’s natural ability to produce endorphins.
From Slate ● Jan. 30, 2026
Cardio is not just good for my heart, but is a great emotional release and gets my endorphins going.
From The Wall Street Journal ● Jan. 5, 2026
I tend toward depression and anxiety, so dancing is an easy way to immediately get your endorphins and it doesn’t feel like as much of a demand as going for a jog.
From Los Angeles Times ● Dec. 12, 2025
Dimple could see, flush from the endorphins of a great performance, why actors and performers got addicted to this kind of thing.
From "When Dimple Met Rishi" by Sandhya Menon
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
