Is It Safe to Take Melatonin Every Night?

Here’s how long you should actually be using this nighttime sleep aid, according to experts.

January 21, 2021


Photo by: RyanKing999/Getty


A 2016 survey by Consumer Reports found that nearly one-third of American adults have trouble falling asleep. Around the same time, the Centers for Disease Control and Prevention (CDC) reported that the same number of Americans get too little sleep overall. And now, we’re experiencing an ongoing anxiety-inducing, global pandemic, which survey shows has led to even more sleep issues for Americans.

With so many people having trouble sleeping, an increasing number are turning to melatonin, a dietary supplement meant to help with sleep. Dimple Ghassi, MD, an internal medicine physician at Albany Med, explains that melatonin is a hormone produced by our brains in response to darkness. “It helps with your circadian rhythms (24-hour internal body clock) and with sleep,” she says. But, does supplemental melatonin work the same way, and is it really safe to take every night? Here’s what the experts have to say.

What do melatonin supplements actually do?

While sleeping pills like Ambien and Lunesta sedate you by slowing down activity in your brain, melatonin supplements don’t actually put you to sleep. “In theory, supplemental melatonin ‘tricks’ your brain to believe it is nighttime and therefore time to go to sleep,” says Mary Ellen Wells, Ph.D., director and associate professor of neurodiagnostics and sleep science at the UNC School of Medicine.

“Melatonin supplements work in a similar way as the body’s natural hormone melatonin,” Ghassi says. Still, it’s not exactly clear what that means — researchers are still trying to figure out exactly how melatonin works and why it seems to help with sleep. Ghassi says it’s possible that melatonin reduces dopamine, a neurotransmitter (chemical messenger in your brain) that helps you stay awake. It’s also plausible that melatonin promotes relaxation by activating certain chemical receptors in your body.

Because of all this, you can’t rely on melatonin alone to fall asleep. It’s important to practice good sleep hygiene, a.k.a. habits that promote sleep: set a consistent bedtime; sleep in a dark, cool, quiet room without your smartphone; avoid big meals before bedtime, drink less alcohol and caffeine in the evening; and get in physical activity during the day. All of this creates optimal sleep conditions so that melatonin can best do its job.

While they’re primarily used to promote sleep, evidence suggests that melatonin supplements may also help treat acid reflux and tinnitus (ringing in your ears) and prevent macular degeneration (vision loss associated with aging).

Are melatonin supplements safe to use?

Melatonin supplements are largely considered safe, but there are some things to keep in mind. The fact that it’s a supplement means that it’s not regulated by the Food and Drug Administration (FDA). “The label may say ‘melatonin’ but the bottle may not have any functional melatonin,” warns Bradley Vaughn, MD, professor of sleep medicine and epilepsy at the UNC School of Medicine. To make sure you’re getting what you think you’re getting, look for supplements with a seal that says USP Dietary Supplement Verified. The United States Pharmacopeia (USP) is a highly trusted third-party laboratory that rigorously tests supplements to ensure that they contain exactly what the label says.

You should also talk to your doctor before starting melatonin supplements — they’ll confirm that it’s safe based on your medical history, conditions and other medications. Like all supplements, melatonin can interfere with certain medications. Specifically, melatonin can interfere with certain anticoagulants, diabetes medications and immunosuppressants.

What dose of melatonin should you take?

Many melatonin supplements contain five to 10 milligrams per dose — far more than you need. Vaughn says that between one-half and three milligrams is the appropriate dose for most people, and that you should take it one to two hours before bed. This is when levels of melatonin in your body naturally start to rise, and when supplementing will be most helpful.

If you’re just starting to supplement with melatonin, Ghassi recommends trying one-half milligram to start. If it doesn’t help you fall asleep, gradually increase your dose until it does. However, she warns not to take more than five milligrams a night.

All three experts agreed that it doesn’t really matter what form of supplement you take. Pills, gummies, tinctures and powders will all have the same effect. What matters is that your supplement actually contains the dose it claims to (that’s why looking for the USP seal is important), and that you take the appropriate dose at the appropriate time.

Are there any side effects of melatonin supplementation?

As long as you’re taking an appropriate dose of melatonin — between one-half and three milligrams for most people, and never more than five milligrams — it’s very unlikely that you’ll have any serious side effects. However, Vaughn says that certain less-serious side effects are fairly common: headache, upset stomach and worsened mood throughout the day.

Taking more than five milligrams per day can lead to more side effects. “Higher doses can cause plasma concentrations to rise three to 60 times normal peaks and produce various side effects like daytime sleepiness, increased prolactin levels, hypothermia and impaired physical and mental performance,” Ghassi explains. She also points out that there’s a lack of research on the safety of melatonin for pregnant and breastfeeding women, so it’s best for women in those groups to avoid it.

How long should you use melatonin?

Although melatonin supplements are considered safe to use, Wells points out that “we don’t know yet if there are any long-term negative side effects.” Therefore, experts recommend that it should either be used occasionally — for example, to combat jet lag during travel, or help you sleep during a particularly stressful few days — or regularly for one to two months. Unlike with other sleep medications, you won’t become dependent on melatonin after taking it for a period of time. You won’t experience any withdrawal symptoms after you stop taking it and you won’t need to up your dosage over time to get the same result. Still, it’s possible that your old symptoms — difficulty falling asleep or poor sleep quality — might come back after you stop taking it.

If you use melatonin for a few weeks and it doesn’t help you fall or stay asleep, or if your old symptoms return once you stop taking melatonin, Ghassi recommends speaking with your doctor about other treatments. “The first line of recommended treatment for insomnia is cognitive behavioral therapy (CBT),” she says.

The bottom line? Short-term use of melatonin supplements is a safe way to improve your sleep.

Melatonin is a hormone naturally produced in the body to promote sleep, and taking additional melatonin as a supplement can help boost this effect. There are no serious side effects or significant risks associated with taking a small dose of melatonin before bed occasionally, or for a few weeks. However, because the long-term side effects haven’t been studied, you shouldn’t take melatonin every night for more than a month or two.

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