Making Sense of Melatonin’s Effect on Sleep

If you take a melatonin supplement before boarding an international flight or keep the capsules in the bathroom cabinet for nights when you struggle to fall asleep, you’re not alone. More than 3 million adults reported taking melatonin in the last 30 days and use of the popular supplement has more than doubled, according to the National Institutes of Health.

Melatonin is a hormone produced in the pineal gland that helps regulate the sleep/wake cycle. Your melatonin levels are low during the day and start to increase as bedtime approaches, signaling it’s time for sleep.

“It reinforces the cycle of nighttime sleep and daytime alertness,” explains Dr. David Neubauer, associate professor of psychiatry and behavioral sciences at Johns Hopkins Medicine.

While your body does a good job of regulating its melatonin levels, several factors could throw it out of whack:

The blue light from your smartphone or tablet suppresses the production of melatonin, leading to a shorter sleep duration and poorer sleep quality. One study found exposure to screens between 9–11 p.m. was associated with more than seven nighttime awakenings, leading to a worse mood and increased fatigue the following morning. Neubauer suggests avoiding screens in the two hours leading up to bedtime to ensure the blue light doesn’t interfere with your melatonin levels.

Many travelers count on melatonin supplements to reset their sleep/wake cycle after crossing multiple time zones, says Mahesh Thakkar, PhD, director of research at the University of Missouri School of Medicine. Taking 5 milligrams of melatonin following an intercontinental flight made it easier to fall asleep, improved sleep quality and reduced fatigue, according to research published in Chronobiology International.

“As you get older, you lose the ability to produce sufficient amounts of melatonin,” says Thakkar. One study reports that melatonin levels decline gradually 10–15% per decade. Another showed that older adults had levels that were only 43% of the younger adults.

If you work a rotating night shift, research shows your melatonin levels are lower at night — and tend to remain lower even on nights when you’re not clocking in after dark, which can make it harder to sleep.

Taking an over-the-counter melatonin supplement is considered a safe option for increasing hormone levels and promoting sleep.

“If you think you need something to help you sleep, [melatonin] is the safest thing to take,” Thakkar says.

Instead of popping a capsule right before crawling between the sheets, Neubauer suggests taking melatonin 4–6 hours before bed. Increasing your melatonin levels earlier in the evening gradually increases the drive to sleep so you’re ready to drift off when you crawl between the sheets. A dose of 1–3 milligrams should be all you need to drift off into dreamland, he adds.

“Melatonin shouldn’t be thought of as a sleeping pill [because] it’s not directly sedating,” Neubauer says. “Taking it can help quiet down your circadian arousal to help facilitate sleep onset.”