mel·​a·​to·​nin | \ ˌme-lə-ˈtō-nən How to pronounce melatonin (audio) \

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

Clocking in those all-important Zzz's is essential to staying healthy and happy, and for some folks, taking a melatonin supplement does the trick for helping get a good night's sleep. Allure, "Melatonin Is Trending in Skin Care Lately, But Can It Really Benefit Your Skin?," 20 Mar. 2019 According to experts, people need a certain amount of melatonin for a good night's sleep, which is why the longer, darker days of winter are a no-no for your cycle. Elizabeth Gulino, House Beautiful, "Research Says This is Actually the Worst Month For Your Sleep Cycle," 28 Feb. 2019 Put down your phone: The artificial light late at night can interfere with melatonin production. Caroline Picard, Good Housekeeping, "What You Need to Know About OTC Sleep Aids, According to Neurologists," 30 Jan. 2019 But between 2007 and 2012, the rates of melatonin use in the United States more than doubled. Ashley Fetters, Bon Appetit, "How Sleep Became a Wellness Fixation," 29 May 2018 Walnuts are one of the best food sources for melatonin, a hormone that helps regulate the body clock for a better night's sleep. Woman's Day Kitchen, Woman's Day, "Pear & Walnut Salad," 21 Dec. 2018 Use of supplements that primarily contained vitamins and minerals remained stable over time, but use of herbal, non-vitamin, or non-mineral supplements increased, driven by the use of melatonin for sleep and omega-3s. Alexandra Sifferlin, Time, "A Third of Children Use Dietary Supplements. Here’s Why Researchers Say That’s Concerning," 18 June 2018 But even in Eastman’s lab studies, when exposures to light, darkness and melatonin are carefully controlled, some people’s bodies adjust more quickly than others. Emily Sohn, Washington Post, "Time-zone changes can leave people worried about jet lag," 7 July 2018 In totally blind people who cannot see light, melatonin is a big one. SELF, "We Asked a Doctor How Much You Need to Care About Your Circadian Rhythm," 4 Sep. 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

mela-, extracted from Greek melan-, mélās "black, dark" + -tonin (in serotonin); so named because the hormone can lighten skin color in animals by reversing the effect of melanocyte-stimulating hormones — more at melano-

Note: The word was probably introduced in the first published description of the hormone's isolation: Aaron B. Lerner, et al., "Isolation of melatonin, the pineal gland factor that lightens melanocytes," Journal of the American Chemical Society, vol. 80, no. 10 (May 20, 1958), p. 2587.

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23 Apr 2019

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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 How to pronounce melatonin (audio) \

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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