serotonin

noun

se·​ro·​to·​nin ˌsir-ə-ˈtō-nən 

ˌser-

: a phenolic amine neurotransmitter C₁₀H₁₂N₂O that is a powerful vasoconstrictor and is found especially in the brain, blood serum, and gastric mucous membrane of mammals

Examples of serotonin in a Sentence

Recent Examples on the Web

Normally, serotonin released between nerve cells is reabsorbed back into the sending cell, but SSRIs partially block that reabsorption process, allowing more serotonin to remain available for communication between brain cells. —Daryl Austin, USA Today, 23 June 2026

As the Mayo Clinic explains, Duloxetine is a type of selective serotonin and norepinephrine reuptake inhibitor (SSNRIs) which works by increasing serotonin and norepinephrine in the brain. —Cara Lynn Shultz, PEOPLE, 15 June 2026

While there are plenty of ways to work the creamy pastel into your summer wardrobe—from breezy dresses to accessories—an even better way to carry that serotonin boost is on your nails. —Amanda Le, InStyle, 14 June 2026

The spice is thought to increase levels of serotonin (the mood-boosting hormone) in the brain, which may have positive effects on anxiety and depression. —Jillian Kubala, Health, 9 June 2026

Word History

Etymology

sero- + ton(ic) entry 2 or tone entry 1 + -in entry 1, probably after angiotonin, earlier name for angiotensin — more at angiotensin

Note: Term introduced by Maurice M. Rapport, Arda Alden Green and Irvine H. Page in "Crystalline serotonin," Science, vol. 108, Issue 2804 (September 24, 1948), pp. 329-330: "The general behavior of the crystalline substance is suggestive of its homogeneity. We would like provisionally to name it serotonin, which indicates that its source is serum and its activity is one of causing constriction."

First Known Use

1948, in the meaning defined above

Phrases Containing serotonin

• selective serotonin reuptake inhibitor

Rhymes for serotonin

• calcitonin
• digitonin
• melatonin
• kronen
• onan
• phonon
• ronin
• santonin

Medical Definition

serotonin

noun

se·​ro·​to·​nin ˌsir-ə-ˈtō-nən  ˌser- 

: a phenolic amine neurotransmitter C₁₀H₁₂N₂O that is a powerful vasoconstrictor and is found especially in the brain, blood serum, and gastric mucous membrane of mammals

called also 5-HT, 5-hydroxytryptamine