Melatonin
OTHER NAME(S): melatonin, N-acetyl-5-methoxytryptamine
Overview
Melatonin is used for various sleep problems. It is a hormone made by your brain that helps your body set its internal clock. Your brain makes more melatonin when it gets dark out, which signals your body to sleep. Common side effects may include dizziness, sleepiness, or headache. Before taking melatonin, make sure to tell your health care provider about any health conditions you have or medicines you are taking.
Uses
What is melatonin used for?
Melatonin is commonly used for certain short-term sleep problems, including the following.
- Trouble sleeping (insomnia)
- Jet lag
- Sleep-wake disorders (circadian rhythm disorders)
The benefits of melatonin for other uses are not well defined.
The Food and Drug Administration (FDA) has not reviewed melatonin for safety and effectiveness, and it is not approved by the FDA. Learn more about dietary supplements here.
How does melatonin work (mechanism of action)?
Melatonin is a hormone made by your brain. It helps your body set its circadian rhythm, which is like its internal clock. Your brain releases more melatonin when it is dark out, which signals your body to sleep.
Taking melatonin when it is time to sleep can increase the levels of melatonin in your body. This may help you fall asleep faster if you have insomnia or jet lag. If you have sleep-wake disorder and have trouble falling asleep at night, taking melatonin may help you reset your sleep schedule.
Melatonin may also have some other effects in the body, such as acting as an antioxidant. But it is not clear if or how melatonin works for other uses.
How is melatonin supplied (dosage forms)?
Melatonin is a dietary supplement that comes in various forms, such as a capsule, liquid, or tablet that is swallowed and a gummy or tablet that is chewed and swallowed.
How should I store melatonin?
You should store melatonin according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.
Side Effects
What are the most common side effects of melatonin?
The most common side effects of melatonin are listed below. These side effects may vary depending on the dose you are taking or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.
- Dizziness
- Drowsiness
- Headache
- Nausea
- Increased bedwetting (in children)
There may be other side effects of melatonin that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of melatonin?
While less common, the most serious side effects of melatonin are described below, along with what to do if they happen.
Severe Allergic Reactions. Melatonin may cause allergic reactions, which can be serious. Stop taking melatonin and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching or skin rash
- Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
Precautions
Who should not use melatonin?
Allergies to Ingredients. People who are allergic to any of the following should not take melatonin.
- Melatonin
- Any of the ingredients in the specific product
Your pharmacist can tell you all of the ingredients in the specific melatonin products they stock.
What should I know about melatonin before using it?
Melatonin is a dietary supplement. It cannot be marketed to treat or cure a disease.
Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.
Keep melatonin out of the reach of children.
Melatonin can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how melatonin affects you.
Some people use melatonin for trouble sleeping (insomnia). If you have insomnia, it is important to make sure that you have the right sleeping conditions and good sleep-related habits. This is known as good sleep hygiene. Learn more about sleep hygiene here.
If you are taking melatonin as a gummy, chew the gummy well before swallowing. If you are taking liquid melatonin, use an accurate measuring device to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist what measuring device to use.
Children who have not yet gone through puberty may be at greater risk of some side effects from melatonin, especially if they take melatonin regularly for a while. Talk to your health care provider about the risks of melatonin in young children.
People who are over 65 years old may be more likely to feel drowsy during the day after taking melatonin the night before. Use melatonin with caution if you are in this age group.
Many melatonin products have been found to contain more melatonin than stated on the label, as well as medicines that are not listed on the label. If you switch to a new bottle or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.
The FDA has not tested melatonin products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.
What should I tell my health care provider before using melatonin?
Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if melatonin is right for you.
In particular, make sure that you discuss any of the following.
Other Medicines and Supplements.Melatonin may interact with other medicines and supplements. Before taking melatonin, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.
Pregnancy. It is not known if or how melatonin could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant.
Breastfeeding. Melatonin passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.
Interactions
Does melatonin interact with foods or drinks?
There are no known interactions between melatonin and foods or drinks.
It is unknown if drinking alcohol will affect melatonin. But drinking alcohol while taking melatonin may increase your risk of dizziness or drowsiness. Alcohol may also make it harder for you to fall asleep.
Does melatonin interact with medicines (drug interactions)?
Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
In particular, make sure that you discuss if you are using any of the following before taking melatonin.
- A benzodiazepine, such as clonazepam (Klonopin), diazepam (Valium and others), or lorazepam (Ativan and others), which is a medicine used for anxiety, muscle spasms, or seizures
- Any medicine that causes dizziness and sleepiness, such as prescription pain medicines, sleep medicines, or medicines for anxiety
The interactions between melatonin and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with melatonin is incomplete. Always check with your health care provider before using melatonin with any medicines.
Dosing
What should I do if I accidentally use too much melatonin?
If you or someone else has used too much melatonin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
Melatonin is available in many different doses and forms. It is usually taken about 30 to 60 minutes before bedtime. Read the product label closely and speak with a health care provider about how to use melatonin safely. If you miss a dose, skip the missed dose and only take melatonin before bedtime. Do not take double or extra doses.
References
- American Academy of Pediatrics (AAP) News: “Thinking about melatonin to help kids sleep? Ask your pediatrician.”
- Drugs and Lactation Database (LactMed) [Internet]: Melatonin. [accessed 7/19/2025]
- Lancet: “The short-term and long-term adverse effects of melatonin treatment in children and adolescents: a systematic review and GRADE assessment.”
- Morbidity and Mortality Weekly Report (MMWR): “Pediatric Melatonin Ingestions — United States, 2012–2021.”
- National Cancer Institute NCI Dictionary of Cancer Terms: Melatonin. [accessed 7/14/2025]
- National Cancer Institute NCI Drug Dictionary: Therapeutic melatonin. [accessed 7/14/2025]
- National Center for Complementary and Integrative Health: Melatonin: What You Need To Know. [accessed 7/14/2025]
- National Center for Complementary and Integrative Health: Sleep Disorders and Complementary Health Approaches. [accessed 7/14/2025]
- Sleep Foundation: Alcohol and Sleep. [accessed 7/25/2025]