Can You Overdose on Melatonin

Taking melatonin with anticoagulant drugs, such as warfarin (Coumadin), could increase your risk of bleeding.

Melatonin Overdose

In large amounts, melatonin supplements can disrupt your circadian rhythms, which includes your sleep patterns. They may also react with body chemicals to cause other symptoms. However, there is no standard dose as people react differently. This makes it hard to define an overdose.

While melatonin is a hormone naturally produced in the body, taking too much supplementary melatonin can disrupt your circadian rhythm (also called your sleep-wake cycle). It may also cause other unwanted side effects.

So, yes, you can technically overdose on melatonin.

However, a melatonin overdose can be hard to define since there isn’t an official standard safe dosage for everyone.

Some people are more sensitive than others to the effects of melatonin. A dose that might trigger side effects in one person may have little effect on someone else.

Young children should avoid melatonin unless otherwise directed by a doctor. Doses between 1 and 5 milligrams (mg) may cause seizures or other complications for young children.

In adults, the standard dose used in studies ranges between 1 and 10 mg, although there isn’t currently a definitive “best” dosage. It’s believed doses in the range of 30 mg may be harmful.

In general, starting low and moving up slowly and carefully is better if you see encouraging results. Speak with a doctor if your sleep problems persist.

A safe dose of melatonin is the lowest dose that’s effective in helping you fall asleep without causing side effects. Generally, a dose between 0.2 and 5 mg is considered a safe starting dose.

A safe dose will depend on your body weight, age, and sensitivity to the supplement.

Too much melatonin can have the opposite effect of its intended purpose. It can make it harder to sleep because your circadian rhythms will be disrupted.

An overdose can also leave you groggy and sleepy during the day and give you nightmares or vivid dreams at night. You can also experience:

For some people, too much melatonin can affect their blood pressure. Medications that lower blood pressure, such as calcium channel blockers and beta-blockers, may reduce your body’s natural production of melatonin.

However, taking a supplement to make up for lower melatonin levels may not always be advisable. Be sure to talk with your doctor about melatonin and other supplements you take if you’ve been prescribed medications to help control your blood pressure.

Because melatonin can affect your sleep-wake cycle, avoid taking it with alcohol or caffeine. These can interfere with your circadian rhythm and your natural melatonin production.

Before starting melatonin or any over-the-counter medication or supplement, talk with your doctor. This is especially true if you take other medications.

For example, birth control pills may cause your body to produce more melatonin, so taking a supplement could push your levels into an unhealthy range.

Taking melatonin with anticoagulant drugs, such as warfarin (Coumadin), could increase your risk of bleeding.

You should also avoid taking melatonin if you take corticosteroids to suppress your immune response in conditions such as rheumatoid arthritis or lupus.

If you think you may have overdosed on melatonin, call Poison Control at 800-222-1222.

You should call 911 and seek emergency help if you have symptoms such as:

• shortness of breath
• sudden chest pain
• blood pressure that’s 180/120 mm Hg or higher

These signs may not be related to melatonin or an interaction between melatonin and other medications. However, they shouldn’t be ignored, as they can indicate a medical emergency.

Though melatonin can be very helpful for some people needing a little extra help falling and staying asleep, it’s not for everyone. You may not tolerate it well, even at low doses. You may find that it doesn’t help you sleep, regardless of the dose.

If insomnia is a problem, talk with a sleep specialist. There may be other lifestyle changes you can make that can help, such as cutting back on caffeine and alcohol or changing your bedtime routine.

You’re not likely to have any serious medical problems due to taking melatonin but you should treat it carefully.

The Food and Drug Administration doesn’t regulate this supplement, so there are no official dosing guidelines to follow. For further questions, talk with a doctor, a healthcare professional specializing in sleep health, or a pharmacist.

Last medically reviewed on November 7, 2022

Can You Overdose on Melatonin?

Danielle writes in-depth articles about sleep solutions and holds a psychology degree from the University of British Columbia.

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Medically Reviewed by

Dr. Abhinav Singh, Sleep Physician

Dr. Abhinav Singh

Dr. Singh is the Medical Director of the Indiana Sleep Center. His research and clinical practice focuses on the entire myriad of sleep disorders.

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Melatonin is a hormone that plays a significant role in the regulation of sleep and circadian rhythms. Dubbed the sleep hormone, melatonin is formed in the brain’s pineal gland in response to falling light levels to prepare the body for sleep.

In recent years, melatonin supplements marketed to treat a variety of sleep disorders have become common. From 2007 to 2012, melatonin use in the U.S. doubled Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference and it now ranks as one of the nation’s most popular supplements. Its popularity stems in part from its image as a natural alternative to traditional sleep medications, which are known for side effects. However, this does not mean melatonin supplements are harmless.

It is important to be aware of the safety risks posed by taking too much melatonin. We take a closer look at melatonin dosing, potential symptoms of a melatonin overdose, and when to contact a doctor.

How Much Melatonin Is Safe to Take?

Melatonin is available to purchase in any quantity, without a prescription in the U.S. However, there is currently no formal consensus on the optimal dosing regimen for this supplement. Studies frequently use doses ranging from 0.1 to 10 milligrams Trusted Source National Center for Biotechnology Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference , but 1 to 5 milligrams is often considered an appropriate amount to start.

There are many challenges to determining the appropriate amount of melatonin for any one person to take. Individual responses to this supplement can vary considerably due to factors that are not fully understood but can include age, gender, specific sleep issues, other health conditions, and timing of administration.

In addition, not all melatonin supplements are created equal. Differences in preparation can significantly alter Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference melatonin’s impact. Depending on the formulation, taking 1 to 10 milligrams of melatonin can raise the body’s melatonin blood levels anywhere from 3 to 60 times the normal amount.

Melatonin users should also be wary of the dosages listed on supplement labels, which have shown to be alarmingly inaccurate. A random sampling Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference of 31 brands of melatonin supplements determined that most did not contain the labeled dose, with the actual amount ranging anywhere from less than 80% to nearly 500% as much. Additionally, over one quarter of the supplements contained serotonin.

Despite the lack of data and variability around dosing regimens, with typical use, melatonin is largely considered safe Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference and is generally well-tolerated in healthy adults. The risk of side effects Trusted Source National Center for Complementary and Integrative Health (NICCH) NCCIH funds and conducts research to help answer important scientific and public health questions about complementary health approaches. See Full Reference is low, but can include mild headache, dizziness, nausea, and sleepiness.

Finding Reputable Sleep Supplements

The safety and efficacy of supplements is not closely monitored by the U.S. Food and Drug Administration (FDA). Shoppers should take additional measures to make sure they are purchasing reputable products.

Can You Overdose on Melatonin?

So far, there is no clinical evidence that short-term melatonin use can cause long-term problems in healthy adults. However, it is important to discuss melatonin supplementation with your doctor, as they can help you determine the proper dosage. Starting with the lowest possible dose is typically recommended. This can help prevent unwanted side effects.

It is also important to note that high-quality studies addressing higher doses of melatonin are lacking. The current body of evidence consists mostly of small studies and case reports.

In one study, 12 adult males were administered intravenous melatonin Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference in doses of 10 milligrams, 100 milligrams, or a placebo. There were no reported differences in sedation among the groups, and there were no harmful reactions. A second study gave five patients 1,000 milligrams of oral melatonin Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference for approximately four weeks. While changes in pituitary hormones were observed, no toxic effects were reported.

What Are the Symptoms of a Melatonin Overdose?

Unwanted or troubling side effects can occur with any supplement, even if it is considered relatively safe. Concerning symptoms have been reported with higher doses of melatonin.

Possible symptoms of too much melatonin include:

• Headache
• Hypotension (low blood pressure)
• Hypertension (high blood pressure)
• Drowsiness
• Vomiting
• Worsening of alopecia areata (an autoimmune disorder causing hair loss)

Because melatonin can affect the cardiovascular, dermatologic, and central nervous systems, those with other conditions may be vulnerable to additional risks. Evidence suggests that melatonin supplementation may induce depression Trusted Source Merck Manual First published in 1899 as a small reference book for physicians and pharmacists, the Manual grew in size and scope to become one of the most widely used comprehensive medical resources for professionals and consumers. See Full Reference , particularly in people predisposed to or currently experiencing it. Research on this topic, however, is conflicting, since some studies have demonstrated the potential for melatonin to treat depression Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference .

People taking blood thinners and benzodiazepines should be careful, as there is a possibility for interaction Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference . Those with epilepsy should also exercise caution, as melatonin has been associated with increased seizures. People who are currently taking other medications or supplements should discuss potential interactions directly with their doctor before taking melatonin.

Research suggests that elderly people, who have lower natural levels of melatonin Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference , may be more sensitive to the effects of melatonin supplements. Therefore, older people are encouraged to check with their doctor before taking melatonin and start with the lowest possible dose.

What Do I Do If I’m Experiencing Symptoms of a Melatonin Overdose?

Compared with most other sleep aids, melatonin clears the body quickly, and its effects are short-lasting. If you are experiencing unwanted symptoms after taking melatonin, you can most likely just wait it out as your body processes the drug. However, when in doubt, it’s always a good idea to seek professional advice. Don’t hesitate to contact your doctor or local poison control for guidance on managing worrisome symptoms or determining whether you need medical care.

What Are the Long-Term Effects of Taking Melatonin?

Minimal research exists on using melatonin beyond a few months. Therefore, there is much we do not know about its long-term effects. There is not even agreement on what constitutes long-term melatonin use.

Most of the concern around taking melatonin for extended periods centers around it’s potential to affect reproductive hormones. While the exact mechanism of action is still unclear, some reports indicate that melatonin may inhibit reproductive hormones Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference .

Is Melatonin Safe for Children?

Further research is needed regarding the safety of melatonin Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference for children.

Nearly 25% of children have difficulty sleeping Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference , and parents increasingly turn to melatonin for help. Between 2007 and 2012, pediatric melatonin use rose seven-fold Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference and is now the second most common natural supplement in this age group.

Despite its prevalence, there are reasons for parents to be cautious about using melatonin. It appears that children may be particularly vulnerable to the possible effects of this supplement on reproductive hormones. Melatonin has been associated with puberty delays Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference , irregular menstruation, and overproduction of the hormone prolactin. It is important to note, however, that research on this topic is conflicting Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference , and experts agree that the topic is understudied.

Parents should also be aware that melatonin may decrease blood pressure or serum glucose levels Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. See Full Reference . Children taking other medications or who have illnesses affecting these systems should consult their doctor before starting melatonin.

Melatonin should only be used for children under the guidance of a doctor. Most pediatric sleep disorders can be managed with behavioral changes, such as proper sleep hygiene and cognitive therapy. Melatonin should not be used before trying other measures.

When Should I Talk With a Doctor?

While melatonin is largely viewed as safe, it is not without risk. Perhaps the most significant risk is what we do not know about this supplement. While you are unlikely to cause any serious damage using melatonin, it’s best to proceed with caution. Seeing a doctor for an accurate diagnosis of a sleep condition can help you determine whether melatonin is suitable for your situation.

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• Melatonin May Be Helpful for People with Insomnia Receiving Inpatient CareDecember 29, 2022 – A study found that small doses of melatonin before sleep may be effective for individuals in inpatient facilities experiencing persistent insomnia after non-pharmacological interventions.
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• Children and Adolescents With Chronic Insomnia May Benefit From MelatoninListed news articles do not represent the opinion of Sleep Foundation and are provided for informational purposes only.