Can You Overdose on Melatonin? Symptoms, Risks, and What to Do

Quick Answer: Yes, melatonin overdose can happen, although severe toxicity is uncommon. Most reported cases cause mild to moderate symptoms such as drowsiness, headache, dizziness, nausea, or confusion. There is no established dose that defines a melatonin overdose for everyone. If you are concerned about how much melatonin was taken, contact Poison Control or a healthcare professional.

Melatonin is widely used as an over-the-counter sleep supplement in the United States. Although it is generally well tolerated when used appropriately, taking a larger amount can increase the risk of side effects, and there is no single dose that reliably predicts how someone will respond.

The effects can vary with age, the amount taken, the type of melatonin product, other medications or substances used at the same time, and underlying health conditions. Children deserve particular attention because accidental melatonin ingestions have increased substantially in recent years.

Can you overdose on melatonin?

Yes. Taking too much melatonin can cause an overdose, although severe toxicity appears to be uncommon when melatonin is taken by itself.

There is no established amount that defines a melatonin overdose in every person. Someone may develop significant drowsiness or other side effects at a dose that causes few problems for someone else. The type of product, age, other medications, and underlying health conditions can all affect the response.

The risk may be greater when melatonin is taken with alcohol, prescription sleep medications, or other substances that cause sedation. Large doses combined with other sedating substances have been reported in more serious cases. [1]

What happens if you take too much melatonin?

Taking too much melatonin most often causes stronger versions of its known side effects.

Possible symptoms include:

• Drowsiness or excessive sleepiness

• Headache

• Dizziness

• Grogginess 

• Nausea

• Irritability or agitation

• Confusion or disorientation

• Vivid dreams

• Stomach cramps or digestive discomfort

Symptoms can vary from person to person. Some people may feel unusually sleepy, while others may develop dizziness, grogginess, confusion, or changes in mood or alertness.

Most mild symptoms improve as the body metabolizes the melatonin. The duration and severity of symptoms can depend on the amount taken and whether the product is immediate- or extended-release.

How much melatonin is too much?

There is no universal dose that can be used to define a melatonin overdose. For adults, lower doses are often enough to produce a sleep-promoting effect, and taking more does not necessarily improve sleep. Higher doses are more likely to cause side effects such as drowsiness, headache, dizziness, or grogginess.

The amount listed on the bottle may not always match the amount actually present in the product. A 2023 analysis of melatonin gummies sold in the United States found substantial differences between the labeled dose and the amount measured in many products. [2] 

Melatonin is regulated as a dietary supplement in the United States rather than as a prescription medication. Dietary supplements do not undergo the same premarket approval process for safety, effectiveness, and dose consistency as prescription drugs. [3]

If you took substantially more melatonin than intended or are unsure how much was taken, contact Poison Control or a healthcare professional rather than relying on a specific milligram cutoff.

Also Read: Melatonin Withdrawal: Is It Real, and What Happens When You Stop Taking It?

What should you do if you took too much melatonin?

If you or someone else may have taken too much melatonin, first check how the person is feeling.

If symptoms are mild, such as sleepiness or dizziness:

• Do not take another dose

• Avoid driving or operating machinery

• Keep the product bottle or package nearby

• Check the amount of melatonin listed per tablet, gummy, or serving

• Estimate how much may have been taken

• Note when the dose was taken

• Check the label for other active ingredients

In the United States, contact Poison Control at 1-800-222-1222 or use the webPOISONCONTROL service for guidance. They can help determine whether the person can be monitored at home or needs medical evaluation. 

Do not induce vomiting unless a healthcare professional specifically tells you to do so.

Also Read: Is Melatonin Safe Long-Term? A Sleep Physician Explains

When is a melatonin overdose an emergency?

Most melatonin exposures do not require emergency treatment, but certain symptoms need immediate medical attention.

Call 911 or seek emergency care if the person:

• Has trouble breathing

• Cannot be fully awakened

• Has a seizure

• Becomes severely confused or disoriented

• Loses consciousness

• Develops symptoms that are rapidly getting worse

If melatonin was taken with alcohol, prescription sleep medication, opioids, benzodiazepines, or another sedating substance, tell the emergency medical team exactly what was taken.

Can children overdose on melatonin gummies?

Yes. Children can take too much melatonin, and accidental ingestion has become an important safety concern.

Melatonin gummies can be especially appealing to young children because they may resemble candy. A CDC analysis estimated that melatonin was involved in about 11,000 emergency department visits among children ages 5 and younger from 2019 through 2022 due to unsupervised medication ingestion. Gummies were the most commonly documented form in cases where the product type was known. [4]

Most pediatric melatonin exposures result in no symptoms or only mild effects, though more serious cases can occur. Earlier CDC data found that pediatric melatonin ingestions increased sharply over the previous decade, with a small number of cases involving hospitalization, mechanical ventilation, or other serious outcomes. [5]

If a child takes melatonin without supervision, keep the original bottle or package and try to determine how many gummies or tablets were taken and the dose. Contact a healthcare professional or Poison Control for guidance, especially if the amount is unknown. 

Melatonin should be stored in its original container and kept out of children's sight and reach.

Also Read: 8 Ways to Help Your Child Sleep Better (Without Melatonin)

Can alcohol or medications make melatonin more risky?

Yes. Melatonin can interact with medications and other substances, and some combinations may increase drowsiness or affect how melatonin is processed in the body.

Medicines that may require extra caution include:

• Prescription sleep medications

• Benzodiazepines and other sedatives

• Some antidepressants

• Antihistamines that cause drowsiness

• Blood thinners

• Seizure medications

• Some blood pressure medications

• Some diabetes medications

• Immunosuppressant medications

Alcohol can also increase sleepiness and impair alertness when used with melatonin.

If you regularly take prescription medications, consult your doctor or pharmacist before starting melatonin, especially if your medications already cause drowsiness or affect your daily functioning.

How long do the effects of too much melatonin last?

Melatonin is usually cleared from the body within several hours, but the effects of taking too much can last longer.

How long symptoms continue can depend on:

• The amount taken

• Whether the product is immediate-release or extended-release

• Age

• Liver function

• Other medications or substances taken at the same time

• Individual differences in how quickly melatonin is metabolized

Drowsiness, grogginess, dizziness, or impaired alertness may persist into the following morning, particularly after a high dose or with an extended-release product.

Until those effects have passed, avoid driving or other activities that require full attention.

Also Read: 10 Best Melatonin Alternatives for Better Sleep

How can you lower the risk of taking too much melatonin?

A few precautions can reduce the risk of accidental or excessive use:

• Follow the dose recommended by your healthcare provider or listed on the product label

• Avoid taking another dose simply because the first one does not seem to be working yet

• Check whether other sleep products or supplements also contain melatonin

• Keep melatonin out of sight and reach of children

• Store it in the original container

• Avoid combining melatonin with alcohol or sedating medications without medical guidance

• Consider products that have undergone independent quality testing

Because the actual melatonin content can vary between supplements, choosing a product that has been independently tested can provide more confidence that the amount in the product matches the label.

Most melatonin overdoses do not cause severe harm, but taking too much can still lead to significant side effects. The level of risk depends on the amount taken, age, other medications or substances involved, and the symptoms that develop.

About the author

Dr. Ruchir P. Patel, MD, FACP, is the Medical Director of the Insomnia and Sleep Institute of Arizona and the founder of Sip2Sleep. He is triple board-certified in sleep medicine, obesity medicine, and internal medicine. Dr. Patel is a multi-year Phoenix Magazine Top Doctor and holds the Inspire Excellence designation.

References:

1. Tripathi, R., Bano, H., & Alam, M. R. (2024). Case report on melatonin overdose: Cause and concern. Sleep medicine: X, 7, 100116. https://doi.org/10.1016/j.sleepx.2024.100116

2. Cohen PA, Avula B, Wang Y, Katragunta K, Khan I. Quantity of Melatonin and CBD in Melatonin Gummies Sold in the US. JAMA. 2023;329(16):1401–1402. doi:10.1001/jama.2023.2296

3. U.S. Food and Drug Administration. (2022, June 2). FDA 101: Dietary supplements. https://www.fda.gov/consumers/consumer-updates/fda-101-dietary-supplements

4. Freeman, D. I., Lind, J. N., Weidle, N. J., Geller, A. I., Stone, N. D., & Lovegrove, M. C. (2024). Notes from the field: Emergency department visits for unsupervised pediatric melatonin ingestion — United States, 2019–2022. Morbidity and Mortality Weekly Report, 73(9), 215–217. https://doi.org/10.15585/mmwr.mm7309a5

5. Centers for Disease Control and Prevention. (2022). Erratum: Vol. 71, No. 22. Morbidity and Mortality Weekly Report, 71(27), 885. https://doi.org/10.15585/mmwr.mm7127a4