What does endorphin mean?
Endorphin refers to any of a class of peptide hormones manufactured naturally by the body — chiefly in the brain and pituitary gland — that act on the same receptors as opiate drugs such as morphine. Their two signature effects are analgesia, dampening the perception of pain, and euphoria, generating feelings of pleasure, calm, or well-being. Endorphins are released during vigorous exercise, laughter, excitement, stress, and even spicy food, which is why they are popularly invoked to explain phenomena like the 'runner's high'. The word itself was coined in the 1970s as a blend of 'endogenous' and 'morphine', literally meaning 'morphine made within'. Although scientists distinguish several distinct endorphin compounds, everyday usage treats them collectively, almost always in the plural. The term carries a broadly positive connotation and has become shorthand for the body's own built-in mood-lifting chemistry.
nounAny of a group of peptide hormones produced by the body, especially the brain and pituitary gland, that bind to opioid receptors and relieve pain while producing feelings of pleasure or well-being.
- A naturally occurring peptide hormone that binds to opioid receptors in the brain to reduce pain perception and induce feelings of euphoria or well-being.
- Loosely, any biochemical agent credited with producing a sense of happiness or calm after exercise, laughter, or other pleasurable activity.
"The runner's high she felt after twenty miles was attributed to a surge of endorphins."
"Exercise triggers the release of endorphins, which can lift mood and dull minor aches."
"Laughing with friends left her flushed with endorphins long after the joke had faded."
The plural is far more common than the singular in everyday usage, especially when discussing exercise, mood, or general well-being.
"A good laugh releases endorphins that can ease tension for hours."
The word 'endorphin' literally means 'the morphine within' — your body brews its own opiates.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of endorphin
The word endorphin was coined in the 1970s by American scientist Choh Hao Li and his colleagues, blending 'endogenous' (from Greek endon, meaning 'within') with 'morphine', the opiate drug whose effects these natural compounds were found to mimic. Its roots thus reach into Greek: endo-, signifying 'inner' or 'within', appears in related words like endocrine and endogenous. The discovery reflected a striking scientific insight — that the human body produces its own substances resembling opium's active ingredients.
Related word forms
How endorphin is actually used
Endorphin is most often encountered in its plural form ('endorphins'), especially in everyday health and fitness contexts. The register is neutral — at home in both scientific writing and casual conversation about exercise or well-being. In strict scientific usage it refers to a specific class of neuropeptides (such as beta-endorphin); colloquially it is used more loosely for any feel-good brain chemical.
Easily confused with endorphin
Morphine is an external opiate drug derived from the poppy plant, whereas endorphins are peptides produced naturally within the body.
Endocrine refers to hormones secreted directly into the bloodstream by glands, while endorphins are specific pain-relieving neuropeptides.