What Is Melatonin & Should You Be Taking It?

The sleep-promoting supplement has exploded in popularity. But can you rely on it to help you sleep every night? Experts talk about the potential side effects, and why it should only be a short-term solution for poor zzz's.

Diptych of a woman sleeping and melatonin
Photo: Getty Images

One-third of adults don't get enough sleep regularly, according to the Centers for Disease Control and Prevention. That's considered less than seven hours of snooze time per night, as research shows that this amount tends to be best for brain health, rejuvenation and overall wellness.

We get it: Even one 30-minute news report is enough to make you lose sleep, not to mention the stress of constant smartphone pings, the ongoing COVID-19 pandemic and pretty much never enough time to get everything done in a day.

To cope with a buzzing brain, more and more Americans are turning to melatonin as a potential patch—basically like a lullaby in a pill or liquid formulation—to rest easier. We were using twice as many over-the-counter melatonin supplements in 2018 than we were in 1999, according to a recent research letter in JAMA. And melatonin is only rising in popularity: Annual sales of melatonin spiked from $285 million in 2016 to $820 million in 2020. That figure is only expected to rise as pandemic and other stresses have mounted since 2020.

So what is melatonin, exactly, and what happens if you take it nightly to try to score some quality zzz's? We spoke to the experts for answers.

What Is Melatonin?

While you might think of melatonin first as a supplement, since it's found in the pharmacy, "melatonin is actually a hormone, not a supplement," explains Carleara Weiss, Ph.D., a New York City-based sleep science advisor at Aeroflow Sleep. "It's mostly known as a sleep hormone, because melatonin slowly builds up during the day and reaches a peak at night, which tells the body that bedtime is approaching."

Just like sleep, melatonin impacts the entire body, Weiss adds. The hormone has antioxidant and anti-inflammatory properties. "Many studies suggest melatonin plays a role in mental, cognitive and cardiovascular health," she says. For instance, one review notes that melatonin may have positive benefits for blood pressure, levels of lipids (e.g., triglycerides and LDL cholesterol) and blood sugar regulation, and some of the effects are due to its antioxidant properties.

Your melatonin level can get thrown off track by travel, shift work, lack of exposure to daytime light or too much blue light exposure from phones. As a result, supplement companies have formulated melatonin to help fill in the gaps.

Who Might Benefit from Melatonin—Plus Who Should Steer Clear

For most people, melatonin shouldn't be "plan A" if you're experiencing sleep challenges, Weiss says. It's mainly a doctor-recommended, short-term course of treatment only for those with:

  • Jet lag
  • Shift work disorder
  • Circadian rhythm disorders
  • Short-term anxiety
  • Some sleep disorders

"The National Institutes of Health confirms that melatonin is generally safe for most people for short-term use," says Bianca Tamburello, a registered dietitian nutritionist for Fresh Communications in Boston. "However you should always check with your primary care doctor before taking melatonin or any other supplement," she says.

There are also some people who should strongly consider skipping melatonin, says Elizabeth Shaw, M.S., a San Diego-based registered dietitian nutritionist and owner of ShawSimpleSwaps.com. If you fall into the following groups, you'll want to talk to your health care provider about how safe melatonin is for you:

  • You are pregnant or breastfeeding (The NIH says that there's a lack of research that shows melatonin is safe in this instance.)
  • You have been diagnosed with certain conditions that affect the liver
  • You have been diagnosed with certain autoimmune conditions
  • You are taking medications that might interact with melatonin supplements, such as blood thinners and epilepsy medications

If you're a parent, know that the use of melatonin among children is controversial, and even low doses may impact a child's development, attention, concentration and daytime sleepiness, Weiss adds. There's also been a sharp rise in adverse events from children taking melatonin, including hospitalizations and calls to poison control centers, reports recent CDC data. (Most often, these were from unintentional ingestions by young kids, as many people now have melatonin in the home.)

How to Choose and Use Melatonin Supplements

If your doctor does recommend melatonin, you can find it in pill, tablet, capsule, powder or liquid form. "Supplements, including melatonin, are not regulated as closely as food products," Tamburello says. She recommends checking the label for a USP-verified mark, a seal that indicates that the supplement contains the ingredients it says it does, is free of harmful contaminants and uses trusted manufacturing processes.

For those occasionally using melatonin to improve sleep quality, Weiss says that it's best to keep the dose low (0.3 to 5 milligrams) and the duration short (four weeks or less of continued use). If the recommended dose doesn't seem to be moving the needle, do not increase your usage without guidance from a health expert.

"Adding an extra dose of melatonin will delay your circadian rhythm. This will push your sleep and metabolism to a later time of the day, increasing the risk of daytime sleepiness and other side effects such as headache, fatigue and difficulty concentrating, and overuse may make it harder to fall asleep the next night," Weiss explains.

Keep in mind that melatonin's "efficacy and safety for long-term use is not yet widely understood," Shaw says. But, as long as your doctor gives you the green light and accurate dose level, a melatonin supplement should be safe for most healthy individuals to take once per night for up to one month. According to the Mayo Clinic, common side effects of melatonin include headache, dizziness, nausea and drowsiness.

What You Might Want to Try Instead of Taking Melatonin

Rather than turning to a pill to get you through those rough patches or long-term sleep struggles, "the best option is to change sleep behaviors, such as reducing exposure to light from electronic devices at least one hour before bedtime, creating a bedtime routine, exercising and meditating," Weiss says.

The experts we spoke to suggest these additional "sleep hygiene" habits to set yourself up for bedtime success:

The Bottom Line

When it comes to getting better sleep, there's a place for both melatonin and improving sleep hygiene, Weiss says. "A well-established sleep hygiene routine can lead to long-lasting improvements in sleep quality in people with insomnia without possible side effects from taking melatonin. However, for people experiencing jet lag and shift work, sleep hygiene alone may not be effective. In that case, a combination of melatonin and sleep hygiene may be needed for sleep," she says.

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