The Health Benefits of Melatonin

A popular sleep aid, melatonin helps reset circadian rhythms and more

Melatonin is a chemical your brain makes when it gets dark outside. It's known as the sleep hormone because it tells you when to go to sleep and wake.

You can also buy melatonin supplements in just about any grocery store or pharmacy. Studies show the supplements are safe and have fewer side effects than many prescription sleeping pills.

Read on to learn more about how melatonin can help reset your sleep-wake cycle and other medical uses.

When to Take Melatonin

Verywell / Joshua Seong

Health Benefits

Hundreds of studies have concluded that melatonin is safe and effective as a sleep aid. While many medications are tested only on healthy adults, researchers have tested melatonin on a wide population, including children. Here are some findings for sleep and other possible health benefits.


Researchers have tested melatonin on people with insomnia, jet lag, shift workers, military personnel, senior citizens, and children. Most studies have focused on short-term use, ranging between a few days to just over three months.

Studies have suggested the following benefits:

  • Fall asleep faster: People who took melatonin fell asleep between 22 and 34 minutes sooner compared to people who took placebo pills.
  • Improve sleep efficiency: That's the time you spend sleeping compared to the time you were in bed.  
  • Help children fall asleep and stay asleep longer. Researchers found this was true even among children with conditions associated with sleep problems, such as autism spectrum disorder and ADHD.
  • Reset your sleep-wake cycle: This is known as your circadian rhythm.

Most research findings suggest modest benefits, like falling asleep 20 minutes sooner. Better quality studies, with larger sample sizes that follow people closely over a longer period of time, are needed.

Age-Related Macular Degeneration 

Some small studies have suggested that melatonin may be helpful in treating certain eye diseases caused by inflammation and aging.

One review looked at experimental studies and clinical trials conducted between January of 1990 and September of 2017. It concluded that melatonin may be helpful in treating:

  • Uveitis: An eye disease that causes sudden redness, swelling and pain in the eye
  • Glaucoma: A group of eye disorders usually caused by pressure within the eye. If it's not treated this can damage the optic nerve, which sends signals from your eye to your brain.
  • Age related macular degeneration (AMD): An eye disease that blurs central, straight-ahead vision in people 65 years of age and older

Researchers don't fully understand why melatonin appears to be protective. They believe it may reduce inflammation and oxidative stress caused by free radicals. These are unstable molecules that can harm cells and tissues.

Most of the eye research has been on AMD. In one study, 100 patients with AMD were given 3 milligrams (mg) of melatonin a day for up to two years. Researchers found that melatonin helped protect the retina of the eye from further damage. This was just one study, though, and it was small.


Many people with autism do not make enough melatonin and have sleep problems.

A 2014 review study found that melatonin helped people with autism fall asleep sooner. They also slept longer and more soundly. The authors added that the improved sleep improved daytime behavior. More studies are needed to determine the ideal dosing and timing of the sleep aid.

Jet Lag

Jet lag happens when you travel across time zones. For at least a few days after traveling, your body's internal clock is still set to where you came from, not where you have arrived. This can make you tired and have trouble focusing. Several studies have found that melatonin helps you get over jet lag symptoms.

The American Academy of Sleep Medicine supports using melatonin to reduce jet lag symptoms and improve sleep after traveling across more than one time zone.


Tinnitus is a condition in which you hear ringing in the ears, even without an external sound of ringing. Melatonin has been examined as a possible therapy to bring some relief.

In a small study, 61 patients with tinnitus were given 3 mg of melatonin at bedtime. The researchers found it reduced inner ear noise and improved the quality of sleep after a month.

Possible Side Effects

There are severe side effects linked to melatonin. They include drowsiness, headache, dizziness, nausea, nightmares In children, possible side effects include agitation and bedwetting.

If you take too much melatonin, you can end up feeling hungover. This usually goes away fairly quickly.

Melatonin may stay active longer in older adults. This could cause daytime drowsiness. There are no reports of fatal overdoses caused by melatonin.

The lack of long-term studies means it's not known whether melatonin is safe for extended use.

Interactions and Warnings

Even though melatonin is sold over the counter, you should talk to your healthcare provider before taking it. This is especially true if you already take medication for other health problems. Melatonin may affect how your body processes certain drugs, increasing or decreasing those drugs' effects.

These include:

  • Blood thinners: If you take medicines to prevent blood clots, taking melatonin may increase your risk of bleeding.
  • Anticonvulsants: If you take epilepsy drugs, the interaction may weaken seizure prevention.
  • Sedatives, tranquilizers: Melatonin may increase the calming effect of these medications.
  • Blood pressure medications: If you have hypertension, melatonin may raise your blood pressure.
  • Diabetes medications: People with diabetes may have higher blood sugar levels while taking melatonin.
  • Immunosuppressants: People with autoimmune diseases take drugs to weaken the body's immune system response. People who have had an organ transplant take drugs to stop their bodies from rejecting their new organs. Melatonin may make these medicines less effective.
  • Contraceptives: Some birth control medicines may increase melatonin levels, making you feel drowsier.
  • Luvox (fluvoxamine): People with obsessive-compulsive disorder (OCD) may take Luvox to prevent unwanted thoughts or repeated actions, like washing their hands. The drug can increase melatonin levels, making you feel drowsier.

Pregnant or nursing women shouldn't take melatonin, because there isn't enough evidence to know if it's safe.

Dosage and Preparations

Melatonin is sold as tablets, lozenges, and gummies.

There are no official dosing guidelines for melatonin. It typically comes in doses ranging from 1 mg to 10 mg.

It's best to start with the lowest dose. Slowly increase the amount until you find what works for you. In research studies, 3 mg of melatonin was a commonly used dose.


Melatonin is sold without a prescription in most grocery stores and pharmacies. It's a dietary supplement. The Food and Drug Administration (FDA) does not require the same evidence of safety and effectiveness for supplements as prescription and over-the-counter medications.

When to Take Melatonin

Melatonin plays a critical role in regulating your sleep-wake cycle. So it should be taken at the right time of day. Your brain naturally makes melatonin from sundown to sunrise. These supplements take about 30 minutes to reach peak levels in your blood.

Most people take melatonin about an hour before going to bed.

However, there are certain conditions when it helps to take it at other times.

  • For trouble falling asleep: Take melatonin 30 minutes before bedtime. 
  • For night owls: People with delayed sleep phase syndrome may want to take melatonin several hours before the desired bedtime. For example, if you usually fall asleep at 2 a.m., but you want to go to bed at 11 p.m., try taking melatonin as early as 9 p.m.
  • For early birds: If you have symptoms of advanced sleep phase syndrome, where you fall asleep very early and wake up early, treatment is usually bright light timed to delay sleep onset. Melatonin may be used either closer to the desired bedtime or after about a half-sleep period. This should be discussed with a sleep specialist.

What to Look For 

The FDA doesn't monitor how companies make food supplements or their quality. So the dose you buy may not be what the label says.

A 2017 study analyzed 31 melatonin supplements. The levels of melatonin ranged from 83% lower to 478% higher than what the product labels said. Also, in some cases different bottles of the same product varied drastically.

That's why it's a good idea to buy a brand that has been certified by Consumer Lab or the US Pharmacopeial Convention.


Melatonin can help you fall asleep sooner and stay asleep longer. Researchers have tested the supplements in a wide range of people, including children. Studies show the supplement can help you reset your natural sleep-wake cycle.

There are no serious adverse effects associated with taking melatonin. That's important to healthcare providers because many prescription sleep medicines can cause serious or bothersome side effects.

Melatonin is sold over the counter in most grocery stores and pharmacies. Still, it's a good idea to talk to your healthcare provider before trying it. This is especially true if you already take medications for certain health problems. Melatonin can impact how other drugs work in your body.

A Word From Verywell

Not sleeping enough can affect your work, school, and how you behave around others. It can impact your mental and physical health, increasing the risk of depression, obesity, and heart disease.

Melatonin is widely considered effective and safe for short-term use. Studies suggest it can help you get the rest you need to stay healthy. If your problem persists, consider seeing a sleep specialist.

Frequently Asked Questions

  • Is it OK to take melatonin every night?

    Most of the research has only looked at short-term usage which ranges from a few days to 13 weeks. There isn't enough evidence to know whether long-term use of melatonin is safe.

  • How much melatonin is too much?

    There's little research to suggest it's possible to overdose on melatonin, even at very high dosages, although some people may be especially sensitive to it. For example, older people, who naturally have lower melatonin levels, should consult their healthcare providers before taking melatonin and may be advised to stick to relatively low doses.

  • How long does melatonin stay in the body?

    Melatonin has a half-life of 20 to 40 minutes. In studies, the effects of melatonin have been found to peak after an hour.

  • Will drinking caffeine interfere with melatonin?

    It may, given that caffeine affects naturally occurring melatonin. It's best to stick with non-caffeinated beverages when taking melatonin to help with sleep.

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