melatonin

[ mel-uh-toh-nin ]

/ ˌmɛl əˈtoʊ nɪn /

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noun Physiology.

a hormone secreted by the pineal gland in inverse proportion to the amount of light received by the retina, important in the regulation of biorhythms: in amphibians, it causes a lightening of the skin.

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Origin of melatonin

1955–60; <Greek mélā(s) black + tone + -in²

Words nearby melatonin

melanospermous, melanotic, melanotropin, melanous, melaphyre, melatonin, melaxuma, Melba, Melba sauce, Melba toast, Melbourne

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use melatonin in a sentence

You can even factor melatonin supplements into your regimen.
Try these new tricks for fighting jet lag|Christopher Elliott|August 25, 2021|Washington Post
To know if the new LED could help people who want to sleep better, scientists will have to measure its effect on melatonin.
Sleep-friendlier lighting is on the way|Manasee Wagh|June 15, 2021|Science News For Students
Plus, the LEDs in this and other smartphones still emit enough blue light to affect the body’s internal clock and melatonin production.
Sleep-friendlier lighting is on the way|Manasee Wagh|June 15, 2021|Science News For Students
High levels of melatonin tell the body it’s time to go to sleep.
Can a happy lamp help cure your winter blues?|Erin Fennessy|January 25, 2021|Popular-Science

She cried, she played Wheel of Fortune on her phone, she put herself to sleep with melatonin.
For Years, JaMarcus Crews Tried to Get a New Kidney, but Corporate Healthcare Stood in the Way|by Lizzie Presser|December 15, 2020|ProPublica
He or she can work with you to map out an individualized plan, which may entail taking the hormone melatonin.
Can Changing Time Zones Affect Your Health?|DailyBurn|June 13, 2014|DAILY BEAST
Once your serotonin levels are back up to normal, they can make enough melatonin so you can sleep better, says Dr. Rindfleisch.
10 Reasons You’re Exhausted and What to Do About It|DailyBurn|April 25, 2014|DAILY BEAST
This helps us regulate our cortisol and melatonin levels for a proper wake and sleep cycle.
Change Your Sense: Biohacking for Beginners|Ari Meisel|March 18, 2014|DAILY BEAST
One more thing, take it in the morning otherwise it can disrupt your sleep since vitamin D and melatonin are inversely related.
These Are The 15 Supplements to Keep In Your Medicine Cabinet|Ari Meisel|December 28, 2013|DAILY BEAST
Worse, disruption of melatonin can contribute to obesity and cardiovascular disease as well.
These 3 Apps Will Help You Sleep Better, Feel Great, and Eat Well|Dave Asprey|December 18, 2013|DAILY BEAST

British Dictionary definitions for melatonin

melatonin

/ (ˌmɛləˈtəʊnɪn) /

noun

the hormone-like secretion of the pineal gland, causing skin colour changes in some animals and thought to be involved in reproductive function

Word Origin for melatonin

C20: probably from mela (nocyte) + (sero) tonin

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for melatonin

melatonin

[ mĕl′ə-tō′nĭn ]

A hormone produced in the pineal gland that plays a role in regulating biological rhythms, including sleep and reproductive cycles. In many animals, melatonin also regulates the physiological effects that occur in response to seasonal changes, such as the growth of a winter coat of fur. Chemical formula: C13H16N2O2.

A Closer Look

Melatonin, a natural hormone manufactured by the pineal gland in the brain, communicates information about light to different parts of the body. It helps regulate biological rhythms and plays an important role in the reproductive cycles of many animals. In humans it is best known for helping to regulate the body's circadian sleep-wake cycle. Melatonin production is affected by light exposure to the eyes; melatonin levels rise during the night and fall during the day, becoming almost undetectable. Though it does not actually induce sleep, melatonin can have sleep-promoting effects. Experiments have shown that at high doses melatonin lowers body temperature, decreases motor activity, and increases fatigue. Melatonin production starts falling after puberty, and it can virtually disappear in the elderly, a phenomenon which could help to explain why sleep disturbances are more prevalent among older adults. Marketed as a dietary supplement and touted as a cure-all for insomnia, jet lag, and even cancer and aging, the overall effects of melatonin on human health are still largely unknown.