Melatonin: Side Effects, Dosage, and More

What is melatonin?

Melatonin is a hormone made by your brain in response to darkness. Your body makes it naturally when you’re in a low-light environment, like in the evenings or at night. You can also take melatonin supplements, which are usually synthetic (artificial).

Melatonin tells your body to go to sleep and helps you stay on a regular sleep-wake cycle. It’s also an antioxidant and may play a role in other body functions.

Melatonin: Sources and supplements

Melatonin is found in nature. It’s made by different animals, plants, and microorganisms. Small amounts are also found in wine and certain foods, like:

• Nuts

• Seeds

• Mushrooms

• Olive oil

• Citrus fruits

• Fish 

• Eggs

Though melatonin-rich foods may have benefits, it can be hard to know exactly how much melatonin is in a specific plant or animal product. It can even vary based on what part of the plant you’re eating or where and how the plant was grown. That’s why many people turn to supplements. 

Most melatonin supplements are made synthetically in a laboratory. You can take it as a:

• Pill

• Dissolving tablet

• Gummy 

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It is also available as a:

• Transdermal patch

• Cream

• Gel

• Liquid

Melatonin supplement dosing

The amount of melatonin in products typically ranges from 0.3 mg to 10 mg.

According to the NIH, adults usually take melatonin in doses up to 8 mg for up to 6 months, and children usually take 3 mg for up to 3 months. Be sure to talk to your healthcare provider to figure out which dose of melatonin is right for you. 

Melatonin is available over the counter in the United States. This means you can purchase it without a prescription. 

Common uses for melatonin supplements

People use melatonin to treat:

• Jet lag

• Delayed sleep-wake disorder (trouble falling asleep and waking up at a normal time)

• Sleep problems in children

• Pre- and post-surgery anxiety in adults

• Non-24-hour sleep-wake disorder 

Melatonin may also potentially be helpful for:

• Sleep problems caused by taking beta blockers (blood pressure medication)

• Cancer treatment

• Cancer side effects

• Endometriosis pain

• High blood pressure

• Short-term insomnia

• Insomnia in older adults

• Migraine prevention

• Sunburn prevention (when applied as a topical gel or cream)

• Jaw pain

• Low platelet levels

Melatonin does not seem to be effective for:

• Improving athletic performance

• Improving appetite or weight gain in people who are seriously ill (cachexia)

• Dementia

• Infertility

• Sleep problems caused by working night shifts (shift work disorder)

• Benzodiazepine withdrawal

• Depression

The science behind melatonin

During the day, your body doesn’t produce much melatonin. But in the evening — as the sun goes down and there’s less light — your brain begins to release melatonin. As the amount of melatonin in your body increases, your body becomes more physically relaxed and quiet. 

Melatonin supplements probably won’t make you feel sleepy or help you immediately fall asleep the way sleeping medications can. But it can help your body transition into night mode, making it potentially easier to get to sleep. It also reinforces your body’s regular sleep-wake rhythm (circadian rhythm). 

Melatonin also plays other roles in your body. It acts as an antioxidant, which means it protects your body cells from harm. Melatonin can also boost your immune system and reduce inflammation. 

Melatonin supplement interactions

Some things can raise your risk of melatonin supplement side effects, including:

• Oral birth control pills

• Caffeine

• Fluvoxamine

• Medications that cause drowsiness

Melatonin can make some medications less effective, including:

• Nifedipine (Procardia)

• Seizure medications

• Immunosuppressants

Melatonin can raise the risk of side effects that come with medications including:

• High blood pressure medications (can lower your blood pressure more than intended)

• Blood thinners, such as warfarin (Coumadin)

• Clozapine (Clozaril)

• Medications for diabetes (can lower your blood sugar more than intended) 

• Medications that cause drowsiness

• Methamphetamine (Desoxyn)

Melatonin supplement side effects

Melatonin supplements can cause side effects such as:

• Sleepiness

• Headache

• Dizziness

• Nausea

• Grogginess the following morning

• Depression

• Sleep changes

• Nightmares

Safety of melatonin supplements

The popular sleep supplement may not be safe for some people, including: 

• Pregnant people: It’s unknown if melatonin supplements are safe to use during pregnancy or while nursing. If you’ve been taking melatonin and become pregnant, contact your healthcare provider.

• Older adults: Older adults may be more sensitive to melatonin’s effects. This can raise the risk of next-day drowsiness and other side effects.

• People with dementia: Experts recommend that people with dementia avoid using melatonin supplements.

• People with depression: There’s concern that melatonin supplements could worsen depression symptoms for some people.

• People with bleeding or seizure conditions: There’s concern that this supplement could worsen the symptoms of these conditions.

FAQs

Disclaimer: The FDA does not test supplements for safety and effectiveness. Supplements can contain harmful substances. They can also affect how your medications work. Always speak with your healthcare provider before taking any supplement.

Why trust our experts?

Written by:

Sarah Gupta, MD

Sarah Gupta, MD, is a licensed physician with a special interest in mental health, sex and gender, eating disorders, and the human microbiome. She is currently board certified by the American Board of Psychiatry and Neurology.

Edited by:

Kelsey Abkin

Kelsey Abkin has been working as a journalist since 2016. She has held many titles throughout her career, including editor, content strategist, digital strategist, and writer.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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