Can You Overdose on Melatonin?

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Melatonin supplements are one of the most widely used sleep aids. While proper doses of melatonin supplements may help some people with sleep disorders, taking too much can be unhealthy. 

Although melatonin is generally safe to use, it is possible to overdose on melatonin. An overdose happens when you consume too much of a substance and exceed the recommended limit. Overdosing on melatonin can cause uncomfortable side effects.

For some people, taking too much melatonin may lead to discomfort and unpleasant symptoms. Some symptoms of a melatonin reaction may include:

• Dizziness
• Headache 
• Fatigue
• Mood swings
• Nightmares or vivid dreams
• Skin irritation
• Heart palpitations 
• Nausea 
• Bleeding or bruising for people on blood thinning medication or who have bleeding conditions

Children should not take melatonin supplements without clear guidance from a pediatrician. The safety of melatonin in children has not been determined, and it is important to recognize signs of potential melatonin overdose. Symptoms may include:

• Drowsiness 
• Increased urination at night
• Dizziness
• Headache 
• Agitation

Keep in mind that a supplement being labeled as natural does not mean that it is always safe. Serious health concerns related to melatonin are rare, but there still is not enough information about the overall safety and side effects of high melatonin doses or whether it is safe to use long term.

Before taking melatonin, read the label to make sure you understand the dose. After you take melatonin, watch for potential side effects. Most side effects will stop once you stop taking the supplement. Consider reporting any side effects to the Food and Drug Administration (FDA) through the MedWatch program. And be sure to consult your doctor if you have an unexpected reaction to melatonin. 

The right dose for melatonin supplements can vary. You should reach out to your doctor for dosing guidance before trying melatonin. If you decide to take melatonin supplements, be sure to read and follow the instructions printed on the product label.

A typical dose of melatonin for adults starts at 1 milligram or less. Melatonin is quickly processed in the body by the liver and the kidneys. It typically takes 60 minutes for melatonin to reach its highest levels in the body, but timing can vary based on dosage and whether the melatonin was ingested in tablet or liquid form.. 

Taking melatonin on a short-term basis is safe for most people. But some people may develop side effects or even be at risk for an allergic reaction to the supplement. Certain groups, like people who are pregnant, breastfeeding, or have seizure or bleeding disorders, should avoid taking melatonin without first consulting a doctor.

The product quality and the amount of melatonin included in specific supplements can vary. This variation in melatonin content may alter the amount you end up ingesting. Estimates suggest that melatonin content in supplements is sometimes nearly 500% higher than what is listed on the label. Selecting reputable supplements that have undergone third-party testing helps ensure that the melatonin content matches what is stated on the label.

There’s a variety of dosages. But the best dose of melatonin to start with is just half a milligram. That’s it. Many people overdose on melatonin without realizing, so talk to your doctor before taking melatonin and always remember to use the lowest dose.

Dr. Michael Breus

Will Melatonin Interact with Other Medications?

Melatonin can interact with other medications and supplements. Melatonin may alter how other medications are absorbed and broken down in the body, which can change how the drug works or its side effects. Mixing melatonin supplements with other drugs or supplements may also affect how drowsy you get. 

Make sure to reach out to a doctor if you are taking other medications for other conditions. Your doctor can review your medications to provide insight on possible interactions with melatonin. 

• Blood pressure: People who are taking medication for hypertension may be at an increased risk of higher blood pressure if they take melatonin. High blood pressure usually has no symptoms, but it can increase a person’s risk of heart disease and stroke.
• Blood clotting: Melatonin may slow blood clotting or affect how drugs that prevent blood clots work. Taking melatonin with blood clotting drugs like warfarin may increase the likelihood of bleeding and bruising.

• Depression: Melatonin may change the effectiveness or metabolism of some medications for depression. Also, melatonin by itself may even aggravate symptoms of depression.
• Diabetes: Combining melatonin with medications for diabetes may cause a person’s blood sugar to drop. A study suggests that eating dinner when melatonin levels are high in the body may interfere with the body’s ability to control blood sugar.
• Birth control: It is unlikely that melatonin supplements hinder the efficacy of hormonal birth control, but more research is needed to rule out any potential interactions. Those on hormonal birth control who are experiencing sleep troubles should consult with their doctor before taking any sleep supplements.

Unfortunately, there is not a lot of research available on how melatonin affects children. Experts recommend giving melatonin to kids only under the supervision or guidance of a health care professional. In recent years, hospitalization and serious side effects from melatonin ingestion has increased in children. In 2021, melatonin comprised almost 5% of all child ingestions reported to poison control centers. 

Instead of using melatonin supplements, experts currently recommend behavioral changes, proper sleep hygiene, and cognitive behavioral therapy as safer alternatives for sleep-related conditions in children. 

Melatonin overdose can be intentional or accidental. About 94% of melatonin ingestions in children that were reported to the poison control centers were deemed accidental. However, most hospitalizations in adolescents were a result of intentionally taking too much melatonin.

The CDC cautions that the widespread availability of melatonin, inconsistent melatonin content across supplements, and limited regulation by the FDA can all play roles in the rise of accidental melatonin overdoses and hospitalizations. Some supplements also do not list all the ingredients on their product labels, and some are contaminated with potentially harmful substances.

Fortunately, there are steps you can take to protect yourself and your family from overdosing on melatonin.

• Use proper storage: Use child-resistant packaging to store your melatonin supplements. Be sure to keep drugs and supplements out of the reach of children. Put your melatonin supplements away when not in use, and ensure they are in a location that your child cannot see or reach.
• Check with a doctor: Speak to a health care provider before giving melatonin to a child. Dosing errors are a common reason children get hospitalized. Likewise, if you have an underlying health condition or regularly take medications or other supplements, ask your doctor if it is safe to start taking melatonin.

• Purchase quality products: The American Academy of Sleep Medicine recommends using melatonin products that have a United States Pharmacopeia (USP) Verified Mark on the label. This mark indicates that production of the supplement has passed quality control measures and only contains ingredients listed on the label.
• Get emergency care: If you or someone else is displaying symptoms of melatonin overdose, get urgent medical care or call 1-800-222-1222 to speak with your local poison control center. 
• Avoid long-term use: Melatonin is affordable and it may treat some circadian rhythm sleep disorders like jet lag. But there is not enough evidence on the safety of melatonin use long-term. Due to lack of studies, experts warn against long-term use of melatonin for insomnia treatment.

About The Author

Afy Okoye

Staff Writer, Sleep Health

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Afy is a writer and creative strategist in San Francisco with a master’s degree in international health policy from the London School of Economics. She has written for VeryWell Health, BlackDoctor.org, and Paste magazine and edited peer-reviewed journal manuscripts for Elsevier. Afy says her work with The Sleep Doctor is anything but “sleepy.” She enjoys the opportunity to learn new information and share knowledge that gives people the power to make better choices. Afy also likes to read non-fiction, do creative writing, and travel solo.

• POSITION: Side Sleeper
• TEMPERATURE: Hot Sleeper
• CHRONOTYPE: Bear

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