Scientists Say: Melatonin

This hormone helps control when we sleep


Melatonin is a hormone that helps to control when we sleep and wake up.


Melatonin (noun, “Mell-ah-TOH-nin”)

This one is a real snooze. Melatonin is a hormone — a chemical that is produced in one area of the body that travels through the blood. This hormone is produced in the brain in the pineal gland, which is tucked in a groove just behind the very center of the brain.

Melatonin regulates the body’s circadian rhythm, or how the body functions on a 24-hour cycle. Levels of melatonin in the blood peak at night, during sleep, and drop in the morning when a person wakes up.

Light helps control when melatonin levels rise and fall. When a person is exposed to only external light, their melatonin levels follow a natural pattern. But that pattern can be disrupted by exposure to manmade light sources, such as a smartphone. That can make it more difficult to sleep or wake up on time. Moving from one time zone to another can also disrupt a person’s bodily rhythms. Some people take extra melatonin, in the form of a pill, at night to help them adjust.

In a sentence

The blue light from electronic devices can prompt a person’s body to produce less melatonin, which can sabotage their sleep.

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Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

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