Meaning of endorphin: Endorphins are natural opioid peptides the body releases to reduce pain signaling and contribute to a sense of well-being.

Definition of endorphin

An endorphin is one of a group of naturally occurring peptides, small chains of amino acids, produced within the body that bind to opioid receptors found mainly in the brain and spinal cord. The name reflects this action, blending endogenous, meaning produced within the body, with morphine, a drug with similar effects on the same receptors.

By binding to opioid receptors, endorphins can reduce the transmission of pain signals within the nervous system and are associated with feelings of well-being. Endorphin release increases in response to certain stimuli, including physical exertion, pain, and stress, and endorphins are classified as a type of neurotransmitter because of the way they carry signals between nerve cells.

Endorphins are one of several classes of natural substances involved in modulating pain and mood, and their release works alongside other signaling systems in the body rather than acting as the sole explanation for how pain and stress are regulated.

Used in a sentence

Increased endorphin activity has been proposed as one factor contributing to reduced pain perception during sustained physical activity.

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Good to know

Endorphins are one of several natural systems involved in modulating pain and mood, so effects sometimes attributed to endorphins alone, such as those following exercise, likely involve other signaling systems as well.

Word origin

Where “endorphin” comes from

Formed as a blend of endogenous, meaning produced within the body, and morphine, itself named for Morpheus, the Greek god of dreams, since endorphins act on the same receptors as morphine.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.