mel·​a·​to·​nin | \ˌme-lə-ˈtō-nən \

Definition of melatonin 

: a vertebrate hormone that is derived from serotonin, is secreted by the pineal gland especially in response to darkness, and has been linked to the regulation of circadian rhythms

Examples of melatonin in a Sentence

Recent Examples on the Web

Common over-the-counter sleeping medications have one of four ingredients: melatonin, diphenhydramine, doxylamine, or valerian. Yvette D'entremont, SELF, "I'm a Scientist With Insomnia So I Researched How to Actually Get Better Sleep," 28 Nov. 2018 Another introduced a $150 bedside lamp, the Aromarest, that releases melatonin and aromatherapy. Chavie Lieber, Vox, "Getting a good night’s sleep is a luxury — and can come at a high price.," 9 Oct. 2018 Olly cofounder Ryan’s fix was to tout supplements’ benefits rather than listing endless ingredients — instead of melatonin, Olly sells Restful Sleep. Jancee Dunn, Allure, "Pretty Pills: How Beauty Supplements Changed the Way We View Wellness," 2 Oct. 2018 An algorithm sets an hourly schedule starting a couple of days before the trip, indicating when to seek or avoid light, when to nap and optionally when to incorporate caffeine or melatonin. Ryan Haase, WSJ, "Six Indispensable Apps for Business Travelers," 30 Aug. 2018 Make sure it's Montmorency cherry—that has six times the melatonin of Balaton tart cherry. Denise Foley, Good Housekeeping, "How to Get to Sleep Fast: 8 Simple Ideas," 27 Dec. 2012 But drugstores sell pills that contain as much as five or 10 milligrams of melatonin, Abbott says, far more than our bodies make. Emily Sohn, Washington Post, "Time-zone changes can leave people worried about jet lag," 7 July 2018 The rate of children taking alternative or herbal supplements nearly doubled, to 6.3% from 3.7%, over a decade, fueled by melatonin and fish-oil supplements. Sumathi Reddy, WSJ, "Do Dietary Supplements Help or Hurt Children?," 2 July 2018 The American Academy of Sleep Medicine also recommends taking melatonin. Nicole Defeudis,, "Uplift app says it can deliver a natural remedy to jet lag," 11 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'melatonin.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of melatonin

1958, in the meaning defined above

History and Etymology for melatonin

Greek melas black + -tonin (as in serotonin)

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7 Dec 2018

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The first known use of melatonin was in 1958

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mel·​a·​to·​nin | \ˌmel-ə-ˈtō-nən \

Medical Definition of melatonin 

: a vertebrate hormone C13H16N2O2 that is derived from serotonin, is secreted by the pineal gland especially in response to darkness, and has been linked to the regulation of circadian rhythms

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