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/ Source: TODAY
By Meghan Holohan

Melatonin has fans and skeptics. Many users swear the over-the-counter supplement helps them tumble into dreamland. Others call it useless. But a small new study shows melatonin theoretically promotes better slumber — even if you’re trying to grab Zs in a noisy, bright environment.

The findings may be crucial to global travelers who need to grab shuteye in busy terminals, college kids who bed down in party-pounding dorms — or hospital patients badly in need of rejuvenating rest.

“Sleep environment is very important for sleep quality. However, sometimes sleep environment is hard to change, such as in ICU,” Xiu-Ming Xi, one of the study’s authors, wrote in an email. He's a professor in the department of Critical Care Medicine, Fuxing Hospital and Capital Medical University in Beijing.

Melatonin seems to help people sleep even when it's loud.
Melatonin seems to help people sleep even when it's loud.Still Images / Getty Images

Xi and his colleagues looked at 40 healthy subjects as they slept two nights in a simulated ICU environment. Patients in ICU experience poor sleep because of the constant noise of monitors, bright lights, and lack of natural light, all of which can worsen or slow recovery.

One night, the researchers monitored how participants slept in the ICU without intervention.

For the second night, they divided the subjects into four segments: one group received no intervention; one received 1 mg of fast-release melatonin at 9 p.m.; one received a placebo; and one wore eye masks and earplugs. Both nights, the researchers used a blood test to monitor melatonin levels and a sleep test that tracks brain waves, heart rate, breathing, and limb movements.

Everyone slept terribly on the regular night. On the experimental night, people who received melatonin or wore eye masks and earplugs slept better than the participants who took a placebo. What’s more, those who took melatonin experienced more REM (dream-heavy) sleep than the other groups.

“Melatonin might benefit sleep disturbance, which [is] caused by poor sleep environments,” says Xi.

While these findings might lead to better sleep treatments for ICU patients, the interventions might also benefit people who experience environmental insomnia or jet lag syndrome.

“You can actually use melatonin to bring back the patient to their normal circadian schedule,” says Dr. Alon Avidan, director of the UCLA Sleep Disorders Center, who was not involved in the study.

Melatonin is the only hormone available over-the counter, according to the National Sleep Foundation. People naturally produce it to prime their bodies for sleep.

“Melatonin is secreted in the brain in response to darkness and shuts off the alerting system that comes from the circadian clock,” says Avidan.

Previous studies looking at melatonin supplements have provided mixed results. The reason? Over-the-counter supplements are not regulated and there isn’t a standard dose of melatonin in each one. And, some people, especially older adults, experience the opposite effect and feel anxious and jittery after taking it.

Which vitamins and supplements can you trust? Go here to learn more

Avidan says that doctors use melatonin for jet lag and resetting the circadian rhythms for shift workers, but people frequently take it incorrectly. Most people consume it immediately before sleep, but it works best if taken a few hours before bedtime. He recommends that people interested in taking melatonin talk to a doctor first.

Another problem with melatonin — overuse might cause it to be less effective or even stop the body from producing it naturally.

“My guess is, for individuals who take it chronically, the benefit is quite minimal,” says Dr. W. Christopher Winter, a sleep medicine expert at Charlottesville Neurology & Sleep Medicine in Virginia, who was not involved in the study.

This article was originally published Mar. 18, 2015 at 9:22 p.m. ET.