Home / Melatonin and Sleep / How Long Does Melatonin Take to Work?

How Long Does Melatonin Take to Work?

Jay Summer

Written by

Jay Summer, Staff Writer

Dr. Abhinav Singh

Medically Reviewed by

Dr. Abhinav Singh, Sleep Physician

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Melatonin is a natural hormone made by the brain that helps people fall asleep at night. It is also available as a dietary supplement that may help people with sleep disorders such as jet lag and insomnia. Melatonin supplements may work best when taken a few hours before an individual wishes to fall asleep.

People who struggle to doze off are often curious about options to help them sleep. In fact, nearly one in ten U.S. adults take medicine to help them sleep at least four days a week. The number of people in the U.S. that use melatonin supplements has markedly risen over the last 20 years.

Several factors can affect how melatonin supplements work and the best time to take them, including an individual’s health, lifestyle, and other medications they are taking. People considering taking melatonin supplements should be aware of these factors, the various forms of melatonin available, and potential safety concerns related to using this common supplement.

How Melatonin Affects Sleep

Melatonin makes a person feel sleepy through its effect on circadian rhythms, which are the near 24-hour cycles that affect every cell in the human body. One important circadian rhythm is the sleep-wake cycle, which affects when people fall asleep and when they wake up.

The human brain naturally makes melatonin. Melatonin supplements are also available over-the-counter in the U.S.. In some countries, melatonin supplements are only available with a prescription.

Naturally-Occurring Melatonin

When it is dark, messages from the eyes send signals to the brain to produce melatonin. After melatonin is released into the bloodstream, it binds to proteins in the brain to make people feel tired. Melatonin also turns off other signals that promote alertness.

Although melatonin is best known for its effects on sleep, it has several other functions in the body. According to current research, melatonin may also:

  • Support healthy bones
  • Prevent or reduce damage to cells
  • Reduce inflammation
  • Lower blood pressure
  • Calm anxiety
  • Block or reduce pain
  • Affect the reproductive system
  • Fight tumor development

Melatonin Supplements

Melatonin supplements have a variety of potential uses. Melatonin may help people who have low levels of natural melatonin and difficulty sleeping. When taken a few hours before their bedtime, melatonin helps to reinforce their circadian rhythm. For this reason, melatonin supplements may help some people whose sleep schedules differ from their circadian rhythms.

Melatonin supplements may help reduce symptoms of jet lag. Studies have found that melatonin improves the length and quality of sleep after eastward air travel. People who take melatonin for jet lag after air travel also adjust to new time zones more quickly than people who do not take melatonin.

Melatonin may also help people who constantly fall asleep and wake up later than they want or need to sleep. While some people may stay up late for work, school, or social reasons, some people have a sleep disorder involving markedly delayed circadian rhythms even when they could go to sleep on time. Studies have found that melatonin helped people with this condition fall asleep faster and sleep longer.

Melatonin may also help people who work night shifts to sleep longer and better during the daytime. However, more research is needed to better understand how melatonin works, when night workers should take it, and what dosage works best for this purpose.

Experts have mixed opinions on whether melatonin helps people with insomnia to sleep. Melatonin may help people with insomnia to fall asleep faster, but only by a few minutes.

Supplemental melatonin does not appear to keep people from waking up during the night.


How Fast Does Supplemental Melatonin Work?

The brain ordinarily makes more melatonin about one to two hours before bedtime and most people start to feel sleepy about two hours after melatonin levels rise. Similarly, most people will feel the effects of supplemental melatonin about two hours after taking it. Most research has studied melatonin given one to two hours before bedtime.

Supplemental melatonin comes in many different forms. The way that a supplement or medicine is made affects how quickly it works. Therefore, different types of melatonin supplements may work more quickly or slowly. People considering taking melatonin supplements should talk to their doctors about what form of melatonin may work best for them.

Extended-Release Melatonin

Some pills have a special coating or additive to slow the release of the active ingredient. These kinds of medications and supplements are sometimes called extended-release, controlled-release, sustained-release or modified-release. Extended-release pills take effect more slowly and work longer than regular pills. Extended-release pills should never be crushed, cut or chewed as doing so could be dangerous.

Some melatonin supplements are extended-release pills. While data is limited on how quickly extended release melatonin takes effect, extended release melatonin pills may reach peak levels in the bloodstream later than fast-release melatonin. Experts believe that extended-release melatonin may be better at reducing the number of times people wake up after falling asleep.

Melatonin Patches

The effect of a supplement or medication can also be slowed by releasing it through a patch on the skin. Melatonin patches release melatonin into the bloodstream more slowly than melatonin pills. Studies have also found that melatonin patches reduce time awake after falling asleep and increase time spent sleeping.

Melatonin Melts

Drug makers may also adjust a supplement or medication to make it act more quickly. Some melatonin supplements are available as fast-acting melts that dissolve under the tongue or between the gums and the cheek. Medications and supplements taken in this way are absorbed more quickly than gummy vitamins were.

People should take supplements and medications only as instructed by their doctor or as indicated on the label. Pills that are designed to be swallowed whole may not work well if taken differently than directed.

Melatonin Gummies

Melatonin supplements are widely available as gummies. Researchers have not yet discovered how quickly melatonin gummies take effect. However, studies of gummy vitamins may shed some light on how melatonin gummies compare to melatonin pills.

To date, research findings on how gummy vitamins compare to vitamin pills have been conflicting. While some studies have found that gummy vitamins are better absorbed than pills, others found that gummy vitamins were similar to vitamin pills.

Parents and guardians should take care to keep melatonin gummies out of children’s reach. Children may confuse gummy supplements with candy and gummies may be a choking hazard for young children.

How to Take Melatonin

Melatonin is usually taken one to two hours before bedtime. Travelers taking melatonin to prevent jet lag can time their dosage on their day of arrival based on the desired bedtime at their destination. To reduce the symptoms of jet lag, melatonin can continue to be taken for up to five days after arrival.

Sleep experts have not agreed upon a standard dosage of melatonin. The adult dosage of melatonin is usually between 1 to 5 milligrams. For children, experts recommend lower doses of melatonin than for adults. Parents and guardians should speak with their child’s doctor before giving melatonin to children, and should follow their doctor’s advice on the dosage.

Some medications, herbs, and beverages can increase natural melatonin levels and may magnify the supplement’s effect. People who take melatonin along with any of the following should talk to their doctors about the appropriate dosage:

Higher doses of melatonin do not appear to be more effective than lower doses, but may have higher risks of side effects. For that reason, people taking melatonin supplements should start at a lower dose. If they decide to try a higher dose, then they should increase the dose slowly until they find a dose that works for them. People should talk to their doctor if sleeping problems do not improve after taking melatonin.

Are There Side Effects to Melatonin?

The side effects of melatonin have not been studied in-depth. However, health experts believe that melatonin is probably safe for most healthy adults. The most common side effects reported by people taking melatonin are:

  • Feeling sleepy during the day
  • Headache
  • Dizziness
  • Upset stomach
  • Irritability
  • Strong nightmares
  • Temporary depression

People should not drive or operate heavy machinery within four to five hours after taking melatonin. Melatonin supplements should never be taken with alcohol or other sleeping pills as the combined effects may cause breathing problems or make people too sleepy.

Melatonin supplements may be unsafe for people who are trying to get pregnant. Health experts do not yet know whether melatonin is safe to take during pregnancy or while breastfeeding. People who are pregnant, trying to get pregnant or breastfeeding should speak to their doctors before starting melatonin supplements.

Melatonin supplements interact with many medications, including birth control pills, blood pressure medicine, antiseizure medicine, medicine to weaken the immune system, and blood thinners. People who take any of these medicines should speak to their doctor before trying melatonin supplements.

Melatonin is not regulated by the U.S. Food and Drug Administration (FDA). Research has found that the levels of melatonin in over-the-counter supplements may be different from the dosage listed on the labels. People who use melatonin can find reputable sleep supplements by talking to a doctor, pharmacist, or selecting products that undergo third-party testing.

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About Our Editorial Team

Jay Summer

Staff Writer

Jay Summer is a health content writer and editor. She holds a B.S. in psychology and master's degrees in writing and public policy.

Dr. Abhinav Singh

Sleep Physician


Dr. Singh is the Medical Director of the Indiana Sleep Center. His research and clinical practice focuses on the entire myriad of sleep disorders.


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