Melatonin Overdose: Dosage, Risks, Outlook, and More

Medically Reviewed By Alan Carter, Pharm.D.

Taking too much melatonin, also known as a melatonin overdose, can disrupt your sleep and waking patterns. It may also have other effects on health, and some recorded overdose cases have been serious. Melatonin is a hormone that your brain produces to control your sleep and waking cycle, known as the circadian rhythm. As a result, many people take melatonin to help with sleep issues.

Many clinicians consider melatonin to be relatively safe when taken in appropriate doses over a short-term period. A 2022 research review suggests that melatonin is one of the least toxic medications.

However, like any medication or supplement, melatonin may have side effects that can become serious in some cases, particularly if you overdose.

This article will explain the risks and effects of melatonin overdose that may occur in adults and children. It will also explain other safety concerns related to melatonin, when to seek medical help, and the outlook of melatonin overdose.

A person wearing an eye mask lies on a bed, covered by a blanket.
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The appropriate dosage of melatonin may vary from person to person. This is because it can depend on factors such as your age, weight, and personal sensitivity to the supplement.

Typical doses of melatonin for adults range from 0.3–5 milligrams (mg) taken once per day before sleeping, advises the American Academy of Family Physicians (AAFP).

However, melatonin is available in over-the-counter (OTC) supplements. As a result, the recommended dosage on labels are estimates, and they may not be tailored to your individual circumstances.

Medical professionals may recommend starting melatonin by taking a low dose at first. In fact, the most recommendable dose of melatonin may be the lowest dose that helps you fall asleep without causing any side effects or complications.

Additionally, according to the AAFP, lower doses are often as effective as higher doses.

For individual advice about what dosage may be safe and effective for you, contact your doctor.

Can you overdose on melatonin?

It is possible to overdose on melatonin. Taking too much melatonin can cause negative health effects.

When used incorrectly — for example, when taken at the wrong time — melatonin may disrupt the sleep-wake cycle, according to the Centers for Disease Control and Prevention (CDC) Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source .

This can worsen sleep concerns or insomnia, rather than improve them.

No one quantity of melatonin will lead to an overdose because each person may respond to the hormone differently. A melatonin overdose depends on how much melatonin is too much for you specifically.

Quality and regulation of melatonin supplements

The Food and Drug Administration (FDA) Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source classifies melatonin as a dietary supplement. This means that FDA regulation standards for melatonin are less strict than for other medications.

Some research from 2017 Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source suggests that melatonin products should have stricter regulation standards in the United States and be available only by prescription.

This is because the quality and content of melatonin in OTC supplements can vary.

A 2017 study examined the melatonin content of products and observed that more than 71% of supplements had inaccurate labels. For example, the actual content of melatonin in some products ranged from 83% less than the amount stated on the label to up to 478% more.

Inaccurate labeling can have serious effects and can increase the risk of overdose, particularly for children.

If you are unsure which product to use and in what amount, contact your doctor for advice.

Effects of melatonin overdose

Other symptoms and side effects of a melatonin overdose may include:

Melatonin for children

There is no set guideline for safe melatonin dosage for children.

The Canadian Paediatric Society Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source recommends a 1-mg dose for infants and between 2.5–3 mg for older children with insomnia. Adolescents requiring melatonin treatment may take 5 mg. 

However, research about the long-term safety of melatonin for children is still lacking.

Do not give supplements to children in any dosage before contacting their doctor.

Risks

In many cases, children taking melatonin do not experience any serious side effects. However, in some cases, it has caused serious effects.

According to a 2022 review of 52,000 recorded cases of children taking melatonin, 15% of those children needed hospital care, and 2 children died.

The National Center for Complementary and Integrative Health Trusted Source National Cancer Institute Governmental authority Go to source notes that because people can buy melatonin for their children without a prescription, the risk of overdose may increase.

Children may also be more likely to overdose on melatonin if the supplements are in a gummy or chewable tablet form, since this may increase the appeal of eating the supplement.

Other safety concerns

Like other medications and supplements, melatonin can in some cases present risks to health, especially when taken in high doses.

Side effects of melatonin

Many people do not experience any side effects when taking melatonin at appropriate doses.

However, some people may develop the following side effects, even when taking typically safe doses:

Melatonin may also cause rebound insomnia and dependence, according to a 2016 research review Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source .

Drug interactions

Melatonin can interact negatively with other medications and supplements, such as:

  • high blood pressure medications and supplements
  • blood thinning medications
  • birth control
  • antidiabetes medications
  • sedative medications or supplements
  • anticonvulsants

Other health conditions

Experts say that melatonin may not be safe for you if you have a history of:

Melatonin may also worsen symptoms of depression. In addition, it may not be safe for those who have received a transplant.

Pregnancy and nursing

If you are pregnant or nursing, experts advise not taking melatonin or talking with your doctor first. There is not yet enough evidence to confirm that it is safe.

Taking melatonin may also make it more difficult to become pregnant. However, it is not an appropriate substitute for birth control.

When to seek medical help

Consult your doctor if you have sleeping difficulties or are considering taking melatonin supplements. They can recommend the right dosage for you and advise you on whether the supplements are safe for your individual circumstances.

Seek emergency medical care or call 911 if you develop any of the following symptoms after taking melatonin:

Seek emergency medical care for any suspected unintended consumption of melatonin by children.

If you think that you may have overdosed on melatonin but are not experiencing any symptoms of illness, call Poison Control at 800-222-1222 or contact your doctor promptly. 

Outlook

Melatonin may be safe for adults, and at times children, when used in appropriate doses for a short-term period.

Sometimes serious side effects and complications can occur. However, researchers from a 2020 study suggest that adults who experience an overdose of melatonin can have a complete recovery, without permanent damage to their health.

How your body responds to melatonin will depend on various individual factors. Children may experience more severe effects.

If it is not safe for you to take melatonin, other treatments for sleep concerns can also be effective. Talk with your doctor to find a treatment plan that’s right for you.

Learn more about treatments and outlook for insomnia.

Summary

Melatonin supplements at appropriate doses seem to be safe for short-term use. However, it is possible to experience complications after a melatonin overdose. Symptoms of melatonin overdose may include drowsiness or fatigue, confusion, and vomiting.

Melatonin supplements may also present a risk because they are not regulated strictly by the FDA, and labels often inaccurately state their real concentration levels. Additional risks of melatonin include interactions with other medications and health conditions.

Talk with your doctor or your child’s pediatrician before starting melatonin.

Call 911 or seek emergency medical care for anyone you suspect may be experiencing a melatonin overdose. 

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Medical Reviewer: Alan Carter, Pharm.D.
Last Review Date: 2022 Oct 26
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