Melatonin is famous as the hormone that naturally helps us go to sleep. Our bodies usually produce enough to keep us on a normal sleep-wake cycle, but the modern lifestyle of bright screens, late nights, shift work, and time zone–crossing travel leaves many people reaching for over-the-counter melatonin supplements to try to re-create that natural process. What’s more, anxiety and sleeplessness caused by the pandemic have had people reaching for melatonin more often too.
Americans spent more than $1 billion on melatonin in 2021, a 28% increase from 2020, according to a report from NielsenIQ. About 56% of people said they had COVID-related sleep problems in a 2021 survey conducted by the American Academy of Sleep Medicine (AASM).
While the natural melatonin produced by the body is best, carefully chosen melatonin supplements may help spur slumber, at least in certain situations. However, they can have side effects and interact with medications, aren’t appropriate for all people and circumstances, and need to be taken at the lowest effective dose — you can definitely take too much melatonin. It can cause dizziness, nausea, drowsiness, and even elevated blood pressure if you take too much for too long, said Dr. Randall Wright, director of brain wellness and sleep programs at Houston Methodist.
Just for the record, we’re also talking about melatonin for adults here. Melatonin is not recommended for babies or toddlers, and there are specific guidelines for melatonin use in children.
What is melatonin?
Think of melatonin as a key player in your built-in body clock. Produced by the brain’s pineal gland, the hormone tells you when to wake up and when to sleep, keeping our bodies in sync with the 24-hour day.
“It works in conjunction with light,” said Dr. Rajkumar Dasgupta, an AASM spokesperson. “In the morning, light suppresses the release of melatonin then, at nighttime as the light is going down, melatonin is secreted and hopefully transitions you into some good slumber.”
That gives sleep a chance to work its magic, rebooting our bodies in preparation for a new 24-hour cycle, Wright said.
Melatonin and insomnia
Not surprisingly, people frequently try to use melatonin supplements to address occasional insomnia, which is trouble falling or staying asleep.
The scientific evidence, though, isn’t strong when it comes to using melatonin for that purpose. In one 2020 review of existing studies, melatonin supplements helped people with insomnia but weren’t as effective as cognitive behavioral therapy (CBT), which is one of the first treatments you should consider for chronic insomnia. CBT involves changing your thoughts and behaviors related to certain issues (like sleep, anxiety, or depression).
In another review, melatonin did seem to help adults 65 or older (we produce less melatonin as we age).
Overall, though, the AASM has concluded there’s not enough evidence to support using melatonin for insomnia.
If anything, given its short-lasting action, melatonin may help you fall asleep but not necessarily stay asleep, says Dr. Steven H. Feinsilver, director of the Center for Sleep Medicine at Lenox Hill Hospital in New York City.
Melatonin and jet lag
Another common use for melatonin supplements is to prevent jet lag after long-distance travel.
Research does back this up, Feinsilver said. If you want to try melatonin to get your body back on schedule, the AASM recommends starting supplements before you leave on a trip and continuing for a few days after you arrive.
Small doses taken before you want to go to sleep should do the trick. (More on the correct dosages in a bit.)
Melatonin and shift work
People whose days and nights are upside down because they work varying shifts may also benefit from melatonin supplements.
A 2014 review of seven trials found that 1 to 10 milligrams of melatonin taken after a night shift increased sleep duration by about 24 minutes. (The actual dose didn’t seem to influence the results.) However, other studies have had mixed results or shown no benefit.
If you’re a shift worker and want to try melatonin, the AASM recommends taking the supplement after getting home in the morning. That way, you won’t feel drowsy on your drive home.
Melatonin and other sleep disorders
Scientists have also looked at whether melatonin can help people with a variety of sleep disorders.
There’s some evidence to suggest that melatonin may benefit people with delayed sleep-wake phase disorder (DSWPD) who fall asleep very late and consequently wake up later in the day.
It may also have a role to play in helping folks with REM sleep behavior disorder (RBD), which is when patients act out their dreams while sleeping. An estimated 1% to 2% of the population has the condition, which affects older people more than younger ones and men more than women.
One word of warning: Most of the studies looking at the impact of melatonin on sleep have been small and have only noted relatively modest gains for these conditions, said Dr. Abhinav Singh, medical director of the Indiana Sleep Center.
Melatonin’s side effects and safety
Is melatonin safe? Yes, melatonin supplements are safe, at least in the short term: There haven’t been any long-term (or large-scale) studies to say whether it’s safe to take for more than a month or two.
While safe, melatonin still can have side effects or interact with other medications. Even short-term use can cause side effects like daytime drowsiness, headaches, and dizziness, according to a 2019 study on adverse events linked to melatonin.
Melatonin supplements may also interact with certain medications such as blood thinners, anti-seizure drugs, diabetes medications, and contraceptives. “Let your physician know that you’re taking it,” Dasgupta said.
People who are pregnant or breastfeeding shouldn’t take melatonin. Neither should people with dementia, autoimmune diseases, depression, seizure disorders, diabetes, or high blood pressure. Melatonin can interact with many medications used to treat these conditions and could aggravate depression in people with a preexisting condition.
How much melatonin should you take?
If you’re going to try melatonin supplements, Dasgupta recommends starting with a low dose (about 3 mg) taken two hours before bedtime, although some people need higher or lower amounts. In many studies, researchers use 2 to 5 mg of melatonin, although it can be as high as 10 mg or more, depending on the condition being treated. The body produces an amount that’s closest to a 0.3 mg dose of melatonin, according to the AASM.
In general, you can buy melatonin in 1 to 10 mg doses, although it’s not always easy to know how much you are actually taking.
The Food and Drug Administration doesn’t regulate dietary supplements the same way as prescription medications, which means you may not know exactly what amount is in an over-the-counter product, Wright said.
In fact, in one study of 31 different melatonin supplements, researchers found that most contained wildly variable amounts of melatonin. The dosage varied from lot to lot and between brands, with some containing almost no melatonin and others having a dose much higher than listed. (One type of chewable tablet said it contained 1.5 mg but was in fact 9 mg.) Many also contained serotonin, a mood-altering hormone that’s a potentially dangerous controlled substance.
If you are taking melatonin, look for products that have been independently tested by US Pharmacopeia (USP), ConsumerLab.com, or the NSF International Dietary Supplement program to make sure the product actually contains melatonin in the dosage listed on the label.
Oral melatonin can start making you drowsy in 30 to 45 minutes, Singh said. That means you should refrain from driving and avoid doing other things that could be dangerous when you are sleepy.
It's best to limit the amount of time you use melatonin, as it really isn’t indicated for long-term or chronic use.
“If you find yourself frequently reaching for a bottle of melatonin to assist with sleep, then it may be time to speak with a sleep specialist or bring this up with your primary care doctor,” Singh said.
Other ways to get to sleep without using melatonin
If you have trouble falling asleep, doctors generally recommend trying nondrug options first.
For instance, dimming your lights and shutting off all electronic screens about two hours before bed will cue your body to produce melatonin, Wright said.
Other “sleep hygiene” practices should be in place to give melatonin a chance. That means:
- Little or no alcohol before bed
- Exercise during the day but not before bed
- Meditation or another mind-quieting exercise
- Keeping your bedroom dark, quiet, and at a comfortable (cool) temperature
- Avoiding caffeine (and fluids in general) before bed
- Going to bed and waking up at the same time every day
- Banning screens at least 30 minutes before retiring
“Dietary supplements should be part of the broader picture,” Dasgupta said. “My instinct is to say that melatonin taken at the right time at the right dose will help individuals who have a circadian rhythm disorder. Is it a very potent sleeping aid? Probably not.”