Yes, you can overdose on melatonin

fatigue tired — A melatonin overdose can cause daytime sleepiness and inability to concentrate.
JGI/Jamie Grill/Getty Images

You can overdose on melatonin which causes daytime sleepiness, dizziness, and headaches.
Most people should not take more than 0.5 to 5 mg of melatonin at once.
While melatonin is not addictive, you can become psychologically dependent on it to sleep.
Visit Insider’s Health Reference library for more advice.

Melatonin is a hormone your body naturally produces to induce sleep. It can also be purchased as an over-the-counter oral supplement to help ease insomnia or reset your body clock after traveling to a different time zone.

Melatonin is generally safe and effective in low doses, but you can overdose which can cause adverse side effects. Here is what you need to know about the side effects of melatonin and how to determine how much to take.

Low doses of melatonin cause relatively few side effects, but it is possible to take too much, says Nicole Avena, PhD, an assistant professor of neuroscience at Mount Sinai School of Medicine in New York City.

Melatonin supplements are not regulated by the US Food and Drug Administration (FDA) and therefore have no standardized dose. The typical dosage found in stores ranges from about one to five mg but can be found in doses as high as 10 mg.

Overdosing on melatonin can lead to side effects, including:

Daytime sleepiness
Headaches
Reduced concentration
Mood changes
Nightmares
Dizziness

How much melatonin is too much?

It's hard to say exactly how much melatonin is too much since there is no standardized dose, but it's best to start with the lowest dose possible and work up from there, says Alex Dimitriu, MD, founder of Menlo Park Psychiatry and Sleep Medicine in Menlo Park, California.

There is no known lethal dose of melatonin and no reports of death from taking too much melatonin, Dimitriu says, but taking too much can disrupt your natural circadian rhythm and internal body clock, causing you to actually have more trouble falling asleep.

The effects of taking large doses of melatonin don't appear to be lethal, Dimitriu says, but more research is needed to determine the long-term health implications of melatonin use and the effects of doses larger than 30mg.

How much melatonin should you take?

The right dose of melatonin for you is the lowest possible dose that can help you sleep with minimal side effects, Dimitriu says. This can vary by individual.

Melatonin should only be used occasionally unless you have otherwise been instructed by a physician, Avena says. Melatonin is considered safe in low doses for short-term use, but there is little data available on its long-term effects and more research is needed to determine overall safety.

If you find you are relying on melatonin in order to fall asleep every night, Avena recommends lowering your dosage slowly. You may experience a few nights of less than great sleep as your body adjusts.

Relaxation techniques like meditation or breathing exercises can help you fall asleep without the help of a melatonin supplement.

"It is more important to have healthy sleep habits and a regular sleep schedule, exercise, and minimal stress, than to rely on any supplement, including melatonin for sleep," Dimitru says.

Is melatonin addictive?

Melatonin is not addictive, but taking it every night can cause you to rely on it as part of your bedtime routine.

"People can become psychologically or biologically dependent on any supplement or medication they take, especially with sleep. People start associating substances and behaviors as part of the bedtime routine," Dimitriu says. "The bedtime routine may suffer if some of the parts are missing, whether it be a favorite blanket, bed, or supplement like melatonin."

It is impossible to become physically dependent on melatonin like you could with other substances, like alcohol, Avena says, but you can come to rely on it as a sleep association.

If you find you are needing to take melatonin every night to sleep, you may have another health condition, like anxiety or a sleep disorder that is affecting your ability to sleep, Dimitriu says.

"With melatonin, it is important to maintain healthy habits besides just using a supplement," Dimitriu says, "Our bodies and minds, if healthy and not anxious should be able to sleep naturally."

Insider's takeaway

In small doses, melatonin supplements are a safe and effective way to help you fall asleep, but more research is needed to determine the long-term effects of taking melatonin regularly.

There is no known lethal dosage of melatonin, but taking more than 10 mg can cause side effects, like daytime drowsiness and headaches.

If you are relying on melatonin to sleep, talk with your doctor about ways to improve your sleep hygiene.