Melatonin is a hormone the pineal gland in the brain produces which helps maintain circadian rhythms. It is also available as a natural or synthetic supplement to promote restful sleep.

Melatonin fulfills many functions in the body, but it is mostly known for maintaining circadian rhythms. The circadian rhythm is the body’s internal clock. It tells the body when to sleep, and when to wake.

In humans, the circadian “clock” is in the suprachiasmatic nucleus (SCN) area of the brain. Using the daily pattern of light and dark, the SCN creates and maintains a regular sleep and wake cycle.

Information about light levels reaches the SCN and then passes to the pineal gland deep in the center of the brain. The pineal gland releases melatonin at night and blocks its release during daylight.

Some foods contain melatonin. It is also available as a supplement in pill or gummy form.

In this article, we will look at melatonin’s role in the body, why people take melatonin pills, and whether it causes any adverse effects.

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A person may use melatonin supplements to promote restful sleep.

Studies have reported very few adverse effects of melatonin. Any side effects that do occur are generally mild, such as:

Children taking melatonin supplements may experience these side effects, along with bedwetting and irritability.

As melatonin may have more severe effects on a fetus or newborn, pregnant or breastfeeding women should check with their doctor before using it.

Melatonin is a natural hormone that appears to have only minor side effects. For this reason, researchers have tested it for use as a natural supplement in several medical conditions, including:.

Sleep disorders

Natural melatonin lets the body know that it is time to sleep. Melatonin supplements have had varying success in treating sleep problems.

A 2013 meta-analysis of studies suggested that melatonin helps improve sleep duration, reduce the time it takes to fall asleep, and improve the quality of sleep compared to a placebo.

While melatonin does not work as effectively as some sleep aids, it has fewer side effects than other drugs.

In another review of studies from 2014, melatonin showed promise for preventing shifts in sleep and wake times in people with jet lag and improving sleep in people with insomnia. The benefits of the supplement in shift workers and healthy adults were less clear.


There is evidence that melatonin can relieve some headaches.

In particular, it may be useful for migraine and cluster headaches. However, researchers do not know which formula and dose might work best for people with headaches.


Some clinical studies of colon, breast, renal, brain, and lung cancer suggest that melatonin might support cancer treatment when a person takes it alongside chemotherapy and radiation therapy.

However, the evidence is far from definitive, and scientists need to carry out more research to confirm the link.

The available evidence suggests that melatonin may help combat cancer when it starts, multiplies, and progresses. There are many ways in which this supplement may work on cancer.

Anyone wanting to take melatonin should discuss it with their cancer doctor, or oncologist, to make sure it will not interfere with their cancer treatments

Researchers are trying to pinpoint its specific actions but suggest it holds a lot of promise.

Alzheimer’s disease

Melatonin levels decrease with age. However, this reduction is more pronounced in people with Alzheimer’s disease. A 2013 study found that melatonin appears to slow the cognitive decline associated with Alzheimer’s.


The findings of a 2014 study suggested that melatonin might slightly improve the symptoms of tinnitus. This effect may be due to improved sleep or the antioxidant properties of melatonin.

Protection from radioactivity

Radiation therapy plays a key role in treating many types of cancer. However, it is toxic and can cause severe side effects. Much of the damage radiation causes is due to harmful substances called free radicals.

Melatonin is an antioxidant that helps combat the damaging effects of free radicals, plus it has anticancer effects. Some research suggests that it might provide benefits for people who receive radiation therapy during cancer treatment.

Always talk to an oncologist before taking melatonin to ensure sure it does not interfere with other treatments.

Learn how melatonin might work to improve sleep.

Most doctors, healthcare providers, and other experts consider melatonin as generally safe. However, it can cause side effects when people take it in more than the recommended amounts. Taking too much of this supplement could lead to an accidental overdose.

To avoid this, people should take the correct dose for their age. Anyone thinking about taking melatonin should check with their doctor to make sure it is safe for them.

Melatonin overdose

Symptoms of a melatonin overdose vary from person to person. In some people, taking too much melatonin can increase sleepiness. In others, it can have the opposite effect and produce a state of enhanced alertness.

Signs that a person has overdosed on melatonin include:

Melatonin can lead to a spike in blood pressure if a person takes more than the recommended dose. If a person already has high blood pressure, they should check with a doctor before taking this product. People who take this supplement should report any unusual side effects to their doctor.

Dosage chart

Researchers have not yet worked out the most effective dosages of melatonin, so no clear guidelines exist. The right dosage varies, depending on the person’s age and why they are taking melatonin.

A usual dose in adults is 1–5 milligrams (mg), depending on the use, but doses can vary from 0.5 to 10 mg.

In some cases, a low dose may work better than a high dose. A small dose of around 0.3 mg is similar to the amount that the body naturally produces. Larger doses cause much higher levels of melatonin in the blood.

In children, use the lowest dosage to begin with. In many cases, a child will respond to 0.5 or 1 mg taken 1–2 hours before bedtime. If a child is still unable to sleep within 1 hour of their bedtime, increase the dosage by 0.5 mg every few days.

Younger children often take 1–3 mg at a time, while older children and teens may need slightly higher dosages. Those with significant difficulty falling asleep may benefit from dosages of 3–6 mg.

AgeMelatonin dosage
Children and teens0.5 to 3 mg — or up to 6 mg for those with severe insomnia
Adults for jet lag0.5 to 5 mg, taken several hours before the intended bedtime and continuing for several days after arrival at the destination
Adults for shift work2–3 mg, taken at the end of a shift and before the intended bedtime, but never before driving home
Adults aged 55 and older2 mg once daily for up to 13 weeks, taken 1–2 hours before bedtime

According to the National Institute for Health and Care Excellence, people should take modified-release tablets with food or after eating, but they should take immediate-release formulations on an empty stomach, 2 hours before or after eating.

Learn which factors help determine the right dosage of melatonin.

Melatonin appears to be safe for the short-term treatment of sleep issues. Its long-term safety is not as clear.

Whether melatonin is safe for an individual depends on their age and health.

Scientists have not done enough research to confirm whether it is safe for pregnant and breastfeeding women to take melatonin. Melatonin may cause daytime drowsiness in some older adults. Doctors do recommend it for people with dementia.

Often children can overcome sleep issues by sticking to it a consistent bedtime. For children who still have difficulties with sleeping, melatonin does appear to be safe for use in the short term. Researchers know less about its long term effects on the growth and development of children.

When giving a child melatonin, begin with the lowest possible dosage and only increase it if necessary. Before starting a child on a course of melatonin, speak to a pediatrician for advice.

Melatonin comes in many different forms, including gummies, chewables, and pills, and there is no single recommended dose.

Find out which side effects melatonin might cause in children.

It is essential to take melatonin at the correct time of day. Taking it too early or too late can alter a person’s biological clock and shift their sleep and wake times.

The National Health Service (NHS) recommend taking melatonin 1–2 hours before your desired bedtime which for most is around 8:00-9:00 pm.

People who are traveling and want to take melatonin to prevent jet lag should start taking this supplement a few days before they leave. This will help acclimatize their bodies to the new time zone. It is best to take melatonin 2 hours before bedtime at the destination.

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A person may recover more quickly from jet lag if they take melatonin.

Taking melatonin may help with a few different health conditions, including:

  • jet lag
  • delayed sleep-wake phase disorder (DSWPD)
  • sleep problems in children with attention-deficit hyperactivity disorder (ADHD) and autism
  • anxiety before and after surgery

One report suggests that melatonin may also provide the following benefits by:

  • protecting the heart by reducing blood pressure in people with insomnia
  • having protective effects against cancer and enhancing the impact of cancer treatments
  • reducing stroke damage
  • reducing the damaging effects of obesity on the body by lowering inflammation
  • slowing mental decline in people with dementia

However, more research will be necessary to prove these benefits in clinical trials.

Scientists have discovered melatonin in several foods. Some foods contain more melatonin than others. Eating foods high in this hormone may produce health benefits by increasing the melatonin level in the blood.

Nuts, especially pistachios, contain the highest concentration of melatonin among plant foods. Eggs and fish are also good sources of this hormone.

Other foods with high melatonin levels include:

  • grapes
  • tart cherries
  • strawberries
  • tomatoes
  • peppers
  • mushrooms

Find out which other foods might help people sleep better.

Taking melatonin during pregnancy might help protect the baby’s brain against damage. However, there is not enough available evidence to confirm this benefit.

A 2016 review of studies did not find any evidence that taking melatonin during pregnancy has protective effects on a fetus.

When it comes to promoting sleep, melatonin may not be the best choice during pregnancy. It might interfere with the sleep cycles of the woman and the baby.

Although melatonin is safe overall, there is not enough research on its effects during pregnancy. Women who are pregnant or thinking about getting pregnant should talk to their doctor before taking this supplement.

Find out which other supplements and home remedies can improve sleep during pregnancy.

Some people should avoid melatonin, including those who:

  • take blood thinners or medicines to lower their blood pressure
  • have diabetes
  • have a seizure disorder
  • have had an allergic reaction to melatonin in the past
  • are taking drugs that suppress the immune system, such as after an organ transplant
  • have a bleeding disorder, such as hemophilia
  • have dementia
  • have depression
  • take other drugs that cause drowsiness, such as benzodiazepines, codeine, alcohol, or barbiturates

Alcohol can influence the effectiveness of many medications and supplements, including melatonin.

Drinking alcohol can reduce the effectiveness of melatonin. This may be partly because, as research shows, alcohol can lower the levels of melatonin in the body.

Alcohol may also cause harmful interactions. Read more about combining melatonin and alcohol here.

Melatonin is a natural hormone that the pineal gland produces in response to light and dark cycles. The melatonin sold in a bottle may be natural or synthetic.

The natural melatonin that is available to buy comes from the pineal gland of an animal. Doctors do not recommend the natural form, as a virus may have contaminated it.

Synthetic melatonin does not carry this risk. Manufacturers make it in factories. However, the Food and Drugs Administration (FDA) do not regulate melatonin as they do other drugs and medicines. This means that bottle may not contain the amount of melatonin that the label suggests.

Melatonin is a hormone. The pineal gland in the brain releases it in cycles. Production increases at night when the light outside starts to fade.

Melatonin acts as a chemical messenger. It tells other organs and tissues how to function. Melatonin signals to the body that it is time to go to sleep.

Melatonin is known as the “sleep hormone.” People with low melatonin levels may not sleep as well as those who have higher levels.

According to the National Sleep Foundation, experts do not believe that melatonin is addictive on a short term basis. Unlike other sleep medicines, it does not cause symptoms of withdrawal when people stop using it.

However, scientists need to carry out more long-term research to confirm that this sleep aid is not habit-forming.

Some people do become dependent on melatonin to sleep. They may find that when they stop taking this supplement, they have a harder time falling asleep.

As with any supplement, people need to check with their doctor before they take melatonin. Getting advice from a doctor can help prevent avoid adverse effects, dependency, and possible interactions between melatonin and other medications.

Learn about other types of sleeping pills, including their risks and safety profiles.

Doctors consider melatonin to be generally safe. However, certain groups of people may at greater risk than others. For example: there may be a few risks when certain groups of people take it. Risks with links to melatonin include:

  • allergic reactions
  • side effects, such as dizziness, headache, and nausea
  • low blood pressure
  • daytime drowsiness, which could make driving and operating machinery dangerous
  • interactions with blood thinners, epilepsy drugs, birth control pills, diabetes medicines, and other drugs

Researchers still do not know the long-term safety of melatonin, especially in children and adolescents. The safety of the supplement in pregnant women and their babies is also unclear at this point.

Valerian root is another natural sleep aid. It may help reduce anxiety and relax the body.

Although valerian root has played a role in herbal medicine since ancient Greek and Roman times, there is little evidence to prove that it is effective.

Studies have produced mixed results as to whether valerian root helps with insomnia and other sleep disorders. It has been hard to draw any real conclusions about its effects. The National Institutes of Health suggest that this is because researchers used different types and doses of this supplement in studies.

Melatonin is preferable over valerian root for short-term sleep issues with the body’s internal clock, such as jet lag. Valerian root may be a better option for anxiety-related sleep problems. It may help reduce the time it takes to fall asleep and improve sleep quality.

The National Sleep Foundation says the recommended dose of valerian root is 400–900 mg. Taking it 2 hours before bedtime may help a person sleep, without causing the side effects of stronger sleep aids.

Learn more about the effects of valerian root on anxiety and insomnia.

Zolpidem (Ambien) is a short term prescription medication for managing insomnia. In studies, Ambien helped to decrease the amount of time it took to fall asleep. It also increased the length of sleep and reduced the number of times people woke up during the night.

In a 2019 study, melatonin and Ambien were similarly effective at helping people sleep during hospital stays. Both sleep aids had similar side effects, mainly grogginess and headaches.

Ambien does carry a warning that it can cause abnormal behavior, such as sleepwalking and driving while asleep. In older adults, it is better to try melatonin first. If melatonin does not work, people can try a drug like Ambien.

Discover which sleeping pills are best and how safe they are.

When used over the short term, melatonin appears to be safe. However, its long-term effects are still unclear. Studies have not confirmed whether using it for extended periods causes any problems.

The long-term safety of melatonin for children is especially important. Researchers do not yet know whether it might affect long-term development, the onset and effects of puberty, and other aspects of growth.

Studies to date found that the side effects of melatonin are mild. Larger studies with longer follow up periods will provide more information on how this supplement might affect people over extended periods.

Melatonin has many functions within the human body, most of which we are yet to understand. Based on current research, it is most helpful for sleep issues, such as jet lag, as well as for anxiety.

It also seems that melatonin might be useful in the treatment of some illnesses.

In time, its full potential may become more apparent. However, as the FDA does not regulate supplements, it is best to speak to a doctor before using melatonin.


What lifestyle changes can I try to improve my sleep cycle?


There are a few lifestyle habits you can enact to protect your sleep:

  • Create a sleep pattern of going to bed at the same time every night with a consistent wake-up time, ensuring that you are giving your body plenty of time to sleep. The recommended amount of sleep for adults is 7–9 hours of sleep per night.
  • Cutting down on your daily amount of caffeine or not drinking caffeine later into the day can greatly improve your sleep.
  • Kicking the nicotine habit due to the stimulating effect of nicotine. or avoiding smoking nicotine products a minimum of 45 minutes
  • Monitor your diet. Spicy, acidic, and fatty foods can sometimes cause heartburn which can get worse when you lay down flat. Eating late at night also makes it difficult to sleep. If you are hungry before bed, choose a light, small low-fat and low-sugar snack.
  • Avoid exercise before bed.
  • Create a sleep-friendly environment. For many people blackout curtains to create a dark space and avoiding the use of electronic devices before bed helps to improve sleep and makes it easier to fall asleep. Electronic devices emit a blue light that suppresses melatonin.

Dena Westphalen, Pharm.D. Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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