Key takeaways:
Melatonin is a dietary supplement that many people take to help with sleep. It’s generally safe for adults at a typical dose of 1 mg to 5 mg daily. Doses over 8 mg aren’t recommended, as they can make side effects more likely.
A melatonin overdose isn’t likely to be life-threatening. But it could cause side effects such as headache, nausea, and dizziness or drowsiness.
If you’re concerned about how much melatonin you've taken, contact a healthcare professional or call Poison Control at 1-800-222-1222. If you’re having trouble breathing or you’re unable to wake up someone who has taken too much melatonin, seek emergency care right away.
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You just finished working the late shift and have to be up early tomorrow morning. But you just can’t seem to fall asleep. And this isn’t the first time your work schedule has interfered with your sleep. You’ve thought about taking over-the-counter (OTC) sleep aids or calling a healthcare professional about prescription sleep medication. But maybe a supplement with melatonin seems like a better place to start.
Even though melatonin supplements are considered “natural” products, there are still risks associated with taking them. And it’s not always clear how much to take, or how much melatonin is too much. Let’s take a closer look at the risks of taking too much melatonin.
What is melatonin?
Melatonin is a hormone that your brain naturally makes to help control your sleep-wake cycle. Your brain releases more melatonin when it’s dark outside to let your body know it’s time for sleep. In fact, you release 10 times more melatonin at night than during the day.
Even small amounts of light, such as from a smartphone or laptop, can cause your body to make less melatonin. A drop in melatonin levels may signal your body to stay awake, even at night. This can cause trouble sleeping due to lower melatonin levels than usual.
Can you overdose on melatonin?
Yes — but it’s not likely to be life-threatening if you do. Other sleep medications can cause a dangerous level of sedation if you take too much. But, in adults, there’s no evidence that this happens with melatonin on its own.
There are case reports of serious health problems in adults who combined a large amount of melatonin with other sedating medications or substances such as alcohol. So the risk of overdose is higher if you combine melatonin with other substances.
And, in children, melatonin overdose may be more likely to cause harm. A large review of melatonin ingestions over a 10-year period found that hospitalizations for children are increasing. Serious injury remains rare. But some children required mechanical ventilation, and a small number of deaths were linked to melatonin overdose.
What happens if you take too much melatonin?
When taking melatonin supplements, it’s important to know the possible side effects that can occur. These side effects are more likely if you take high doses of melatonin, and they include:
Headache
Nausea
Drowsiness (including next-day drowsiness)
Dizziness
Vivid dreams
Diarrhea
Side effects of melatonin in children are similar. But children may be more likely to experience nightmares, vivid dreams, or extreme sleepiness.
What should you do if you’ve taken too much melatonin?
If you or a loved one takes too much melatonin, it’s best to contact a healthcare professional or call Poison Control at 1-800-222-1222. They can help you know if you should go to your nearest emergency room or if it’s OK to monitor your symptoms at home.
If you’re having trouble breathing or you’re unable to wake up someone who has taken too much melatonin, seek emergency care right away.
Side effects of melatonin: Daytime sleepiness is the most common. We’ll review what other side effects — like headaches and vivid dreams — you should know about.
Supplements for sleep: There are lots of over-the-counter sleep supplements. Find out what the evidence shows to see which may be best for you.
Melatonin dosing guide: To make sure you don’t take too much melatonin, it’s best to start with the lowest dose possible. We’ll review typical dosing for melatonin.
How long does melatonin last in the body?
Melatonin’s effects can last several hours. It takes your body 1 to 2 hours to lower melatonin levels by 50%. This is called the half-life of the medication. Most people won’t feel melatonin’s effects after this point. But it can take much longer (up to 10 hours) to fully clear a melatonin supplement from your system. So some people may continue to feel its effects during that time.
Keep in mind that these times may be different depending on what type of melatonin supplement you take. Extended-release formulations can last longer in the body.
It’s best to only take melatonin if you can rest for a full 8 hours. This gives your body time to fully clear it, which can help you avoid next-day drowsiness.
How much melatonin should I take?
Melatonin supplements are available in a wide range of dosage forms and doses. Since it’s not an FDA-approved medication, there isn’t a standard recommended dose.
Dietary supplements, such as melatonin, also aren’t regulated by the FDA the same way as prescription and OTC medications. Melatonin supplements aren’t required to go through safety and efficacy testing. And the amount of melatonin in each product can vary.
In fact, a study of various melatonin products showed that 71% of the melatonin supplements tested contained different amounts of melatonin than what was listed on the label. Some melatonin supplements even contained other substances, such as serotonin.
This lack of regulation can make dosing more difficult, as it’s not always clear how much melatonin you’re taking. It’s best to choose products with a certification from an organization like the United States Pharmacopeia (USP). A healthcare professional or pharmacist can also help recommend a trusted brand or formulation.
Typical melatonin dosage for adults
It’s best to start with a low dose of melatonin at first. You can then slowly increase the dose to find what works best for you. Most adults take 1 mg to 5 mg of melatonin. Healthcare professionals often recommend starting with 1 mg to 2 mg of melatonin. However, some research indicates that even lower doses are effective — 0.3 mg or 0.5 mg — with fewer side effects.
Some people may take higher doses of up to 8 mg, but doses over 8 mg aren’t recommended as they’re more likely to cause side effects. And, if you need to take melatonin for more than 6 months at a time, talk to a healthcare professional you trust. There may be a medical issue that’s causing your sleep trouble.
It’s best if you take it an hour or two before bedtime, since it takes a few hours for melatonin to start working.
Is melatonin safe for kids?
Melatonin seems to be safe for children and teens, but only if used correctly. And studies on long-term use are lacking. Melatonin isn’t recommended for children under age 3. If your child is over 3 years, talk to a healthcare professional before giving melatonin to your child.
It’s also a good idea to keep melatonin in your home out of the reach of children. Most overdoses in children younger than 5 are caused by accidental overdoses. And children may be more at risk than adults for serious side effects from taking too much melatonin.
What medications interact with melatonin?
Even though it’s an OTC supplement, melatonin can interact with other medications you take. Some medications can raise melatonin levels in your body. Other medications may be less effective if you take them with melatonin.
Some examples of medications that interact with melatonin are:
Warfarin (Coumadin, Jantoven)
Nifedipine (Procardia, Procardia XL)
Nortriptyline (Pamelor)
Citalopram (Celexa)
Z-drugs, such as zolpidem (Ambien) and zaleplon (Sonata)
Benzodiazepines, such as alprazolam (Xanax) and triazolam (Halcion)
This isn’t a complete list of possible melatonin interactions. It’s best to review your medication list with your pharmacist or healthcare team before taking melatonin. They can make sure there aren’t any interactions you should be aware of.
Frequently asked questions
Death from melatonin overdose is extremely rare. There’s no clear evidence that melatonin alone causes fatal overdose, even at high doses. That said, taking too much can still lead to serious side effects, such as:
Extreme sleepiness
Confusion
Vomiting
Low blood pressure
This is especially true if melatonin is combined with alcohol or other sleep medications. And a small number of pediatric deaths have been reported after melatonin ingestion, though it’s not clear that melatonin itself was the cause.
Taking melatonin every night is generally considered safe in the short term, as long as you’re taking the right dose. But there isn’t enough research on the safety of long-term nightly use. If you find yourself relying on it every night, it’s worth checking in with a clinician — and taking a closer look at your sleep habits — to see if there are other ways to support better sleep.
Unlike many sleep medications, melatonin doesn’t seem to cause true tolerance. So people don’t need to take higher doses over time. If it feels like it’s not working anymore, that may be a sign that the dose or timing is off — or that something else is interfering with sleep — rather than a need to take more.
Death from melatonin overdose is extremely rare. There’s no clear evidence that melatonin alone causes fatal overdose, even at high doses. That said, taking too much can still lead to serious side effects, such as:
Extreme sleepiness
Confusion
Vomiting
Low blood pressure
This is especially true if melatonin is combined with alcohol or other sleep medications. And a small number of pediatric deaths have been reported after melatonin ingestion, though it’s not clear that melatonin itself was the cause.
Taking melatonin every night is generally considered safe in the short term, as long as you’re taking the right dose. But there isn’t enough research on the safety of long-term nightly use. If you find yourself relying on it every night, it’s worth checking in with a clinician — and taking a closer look at your sleep habits — to see if there are other ways to support better sleep.
Unlike many sleep medications, melatonin doesn’t seem to cause true tolerance. So people don’t need to take higher doses over time. If it feels like it’s not working anymore, that may be a sign that the dose or timing is off — or that something else is interfering with sleep — rather than a need to take more.
The bottom line
Melatonin is an OTC supplement that’s commonly used as a sleep aid. Taking a large amount is unlikely to be life-threatening. But higher doses can increase the risk of side effects such as nausea, headache, and dizziness or drowsiness. Starting with a low dose is best, since lower doses are often just as effective and less likely to cause side effects.
If you’re worried about how much melatonin you’ve taken, contact a healthcare professional or Poison Control. Seek emergency care right away for trouble breathing or if someone can’t be woken up.
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References
Boston Children’s Hospital. (2022). Melatonin for kids: Is it effective? Is it safe?
Erland, L. A. E., et al. (2017). Melatonin natural health products and supplements: Presence of serotonin and significant variability of melatonin content. Journal of Clinical Sleep Medicine.
Händel, M., et al. (2023). The short-term and long-term adverse effects of melatonin treatment in children and adolescents: a systematic review and GRADE assessment. EClinicalMedicine.
Labay, L. M., et al. (2019). The importance of melatonin detection in pediatric deaths. Academic Forensic Pathology.
Lelak, K., et al. (2022). Pediatric melatonin ingestions — United States, 2012-2021. Morbidity and Mortality Weekly Report.
MedlinePlus. (2022). Melatonin.
Papillon-Ferland, L. (2019). Should melatonin be used as a sleeping aid for elderly people? The Canadian Journal of Hospital Pharmacy.
Savage, R. A., et al. (2022). Melatonin. StatPearls.
Shenoy, P., et al. (2024). Melatonin use in pediatrics: A clinical review on indications, multisystem effects, and toxicity. Children (Basel).
Society for Endocrinology. (2021). Melatonin. You and Your Hormones.
