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Melatonin: Worth Losing Sleep Over?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on May 12, 2021.

What Is Melatonin?

Melatonin - you've probably seen it in the vitamin section of your pharmacy.

But melatonin is not a vitamin. Melatonin is the hormone your body naturally secretes that tells you when it's time for bed. It's available as a supplement, too.

Natural melatonin is formed from the amino acid tryptophan in our bodies and then released to our melatonin receptors in the brain. It helps to control our sleep and wake cycles. In fact, nighttime melatonin hormone levels are roughly 10 times higher than in the daytime.

Melatonin release is increased each day in response to darkness, peaking at about 2 to 3 AM.

Melatonin Uses

Melatonin has gained wide popularity in recent years.

Synthetic melatonin tablets have been used:

  • to help minimize jet lag
  • to help adjust sleep cycles in the blind
  • for shift-work sleep disorders in people with alternating work schedules
  • for other sleep disorders.

Studies are also looking at its use in seasonal affective disorder (SAD).

But how effective is melatonin and what about its safety?

  • The regulation of melatonin products varies by country.
  • In the U.S., melatonin is can be purchased without a prescription in the pharmacy or health food store.
  • Strengths range from 1 milligram (mg) to 10 mg, and they come as tablets, capsules, oral liquid, lozenges, timed-release forms, and even chewable gummies. Liquid formulations may contain alcohol, so check labels.
  • On average a 120-count bottle costs about $10.00, but this can vary widely around the country.

How Safe Is Melatonin?

In general, melatonin is a relatively safe supplement; and side effects are uncommon. In fact, most side effects occur at a lower or equal rate to placebo (an inactive pill).

However, some people can have side effects from melatonin that can include:

  • Feeling sleepy, weak, confused in the daytime
  • Vivid dreams
  • Depressed mood
  • Headache
  • Loss of appetite, diarrhea, nausea
  • Minor blood pressure changes
  • Back pain, joint pain

Jet Lag Is A Drag

Jet lag is one of the most common uses for melatonin.

Jet lag is much more likely if you cross over several time zones, getting worse with the number of time zones you cross.

Jet lag is a travel problem that causes:

  • difficulty in falling asleep or staying asleep
  • fatigue
  • trouble concentrating
  • constipation.

Given enough time (3 to 5 days), jet lag will usually resolve on its own. This is not always optimal for everyone, especially for busy professionals or eager tourists on the go.

What is the Dose of Melatonin For Jet Lag?

For jet lag minimization, there is a specific way you should take melatonin.

If you are traveling east over several time zones, say from the US to Europe, take the melatonin after dark, 30 minutes before bedtime in the new time zone or if you are on the plane. Then for the next 4 nights in the new time zone, take it again after dark, 30 minutes before bedtime. Appropriately timed light exposure therapy can also be helpful when combined with melatonin for eastward travel.

Westbound travel does not always require melatonin use, and it may not be helpful. If you are heading west, for example, from the US to Australia, a dose is not needed for your first travel night, but then take it for the next 4 nights in the new time zone, after dark, 30 minutes before bedtime, if needed.

Either way, do not drive if you are drowsy when you arrive at the airport.

Initial doses for insomnia or jet lag should start on the lower end of melatonin dosing (0.3 to 0.5 mg), and range upwards to 5 mg. Different doses may be effective for different people. Doses of 3 to 5 mg at bedtime are commonly used.

Are There Drug Interactions With Melatonin?

Yes, there can be some important drug interactions with melatonin; melatonin is structurally similar to serotonin, a neurotransmitter (nerve chemical) found in the brain and other areas of the body.

Melatonin may have a important drug interactions with these medications, possibly increasing the blood levels of melatonin or causing other side effects:

  • Fluvoxamine - avoid with melatonin
  • Sedative-type medications, like zolpidem, triazolam, or lorazepam - avoid with melatonin, may enhance impairment of memory and sedation
  • Blood-thinner medications like warfarin: talk to your doctor before you use melatonin with warfarin
  • Excessive caffeine may blunt your ability to fall asleep more easily, either on its own or when used with melatonin.

This is not a full list of melatonin drug interactions. See a detailed list here.

Tell your doctor or pharmacist about all medicines and vitamins you take, including over-the-counter (OTC) drugs, dietary supplements and herbal products.

Check with your doctor before you take melatonin with any medication. Also, do not stop using any medications without first talking to your doctor.

Liver Enzymes and Melatonin

Melatonin is primarily broken down in the body in the liver (metabolized) by cytochrome P450. Many other drugs are also metabolized by these enzymes.

Theoretically, when melatonin is combined with these other drugs also broken down by the same set of enzymes there can be competition. Why is this a problem? There's only so much enzyme to go around, and blood levels of melatonin (or the other drug) may rise, leading to increased side effects and drug toxicity.

Some drugs that might cause these problems include:

  • caffeine
  • ciprofloxacin (Cipro)
  • deferasirox (Exjade, Jadenu)
  • echinacea
  • fluvoxamine
  • olaparib (Lynparza)
  • warfarin (Coumadin, Jantoven)

This is another good reason to have a drug interaction screen even with OTC supplements, talk to your pharmacist when drugs are added or removed from your regimen, and use melatonin cautiously.

See a list of melatonin drug interactions here.

Melatonin Use in Children

Although melatonin products exist over-the-counter (OTC) for use in children, it is best to only use melatonin for your child under the direction of a pediatrician or other medical specialist.

Causes of insomnia (inability to fall asleep or stay asleep) should always be evaluated in children to determine if there is an underlying medical or behavioral cause. Melatonin should not be used to "force sleep" in otherwise healthy children. Use for children with developmental disorders should also involve behavioral interventions.

According to a meta-analysis published in Archives of Disease in Childhood, children with developmental disorders such as autism spectrum disorder, attention-deficit/hyperactivity disorder, and intellectual disability can have sleep disturbances and may benefit from melatonin treatment when compared to placebo. In this study reviewing 541 children from 9 studies, the authors note that:

  • melatonin significantly improved sleep onset latency, with a mean difference of 28 minutes
  • melatonin increased total sleep time, mean difference of 48 minutes
  • melatonin did not significantly decrease nighttime awakenings.
  • no serious side effects were reported.

Side effects are infrequent with melatonin, but use in children over the longer term is not well studied. Reported side effects with melatonin use in children are:

  • morning sleepiness
  • “fogginess"
  • increased enuresis (bed-wetting)

Doses vary in studies in children and should be determined by your child's doctor.

There is no evidence to support the effectiveness of extended-release melatonin over immediate-release. Liquid preparations of melatonin usually contain alcohol, and should be avoided in children. Parents should select over-the-counter products that only contain melatonin, and not combined other herbal supplements.

Can Melatonin Cause Seizures?

In the past, data reported from Jain and colleagues was mixed on whether melatonin contributed to a greater seizure risk, especially in epilepsy or in children with developmental disorders like autism spectrum disorder or attention-deficit/hyperactivity disorder (ADHD). More recently, the consensus appears to be that melatonin neither increases or decreases the risk for seizures.

You should still seek advice from your doctor before you use melatonin in your child with a severe neurological disorder or with epilepsy, or if they take a drug that may increase their risk for a seizure.

Examples of drugs that might increase the seizure risk include:

  • some antibiotics
  • general anesthetics
  • narcotics
  • ADHD stimulants like methylphenidate (Ritalin).

Be sure to tell your healthcare provider that you use melatonin and always have your pharmacist run a drug interaction check, even with over-the-counter (OTC) medicines.

Electronics and Bedtime

Electronic devices, like iPhones, iPads, and TVs often find their way into the bedroom at night, emitting blue light from their screens. This can be especially problematic for kids.

Researchers have found that the bright light of these devices may lower levels of natural melatonin. The effect was most significant for children just entering puberty, with nighttime melatonin levels suppressed by up to 37% in certain cases.

The study shows that bright light can alter melatonin levels which may be the culprit to a bad night's sleep.

A Hard Day's Night

A hard time getting to sleep at night and staying asleep is a common complaint for many adults. Plus, it can get worse after age 55 as melatonin levels drop drastically as we age. In fact, the CDC has reported that over a third of US adults don't get a good night's sleep.

Insomnia can be due to any number of causes such as:

  • Excessive caffeine, smoking, alcohol use, or late night meals
  • Travel, late-night exercising, mid-day napping
  • Pain, acute or chronic
  • Medication side effects
  • Depression, anxiety
  • Need to urinate
  • Sleep apnea
  • Temperature or humidity
  • Blue light from electronics at night

Melatonin Dosing

Eliminating the fixable causes for your insomnia is the first goal, and referral to a sleep specialist is recommended if there is no success.

Studies have found melatonin doses ranging from 0.5 to 10 mg given 30 to 60 minutes before bedtime to be effective. It's best to start with a lower dose and increase if needed. A trial of melatonin may be worthwhile for insomnia or jet lag, but check with your doctor first and start with low doses from 0.3 to 0.5 mg.

Higher melatonin doses may be associated with more side effects such as headache, next day grogginess, or vivid dreams. According to a Cochrane review, doses over 5 mg appear to be no more effective than lower doses. It is important to note that much higher doses are available for sale in the U.S., but these doses may result in excessively high levels of physiologic melatonin.

Timed-release melatonin may be effective, as well, given 1 to 2 hours before bedtime. However, don't drink alcohol with the time-release preparation; it can disrupt the time-release mechanism. And don't forget, excessive alcohol use at night can lead to early awakening, dehydration and be disruptful to sleep in general, too.

To stay up-to-date and ask questions related to melatonin and sleep-disorders, join the Melatonin Support Group.

Recap: Clinical Use of Melatonin

In the US, melatonin is commonly used for:

  • jet lag
  • sleep disorders and other insomnias.
  • sleep disorders in the blind
  • workers with odd shifts that are disruptful to sleep
  • short-term relief of general insomnia.

Melatonin may be preferable to other sedatives due to lower risk of side effects and addiction.

In the US, melatonin is easily accessible at the pharmacy for a relatively low cost. Dosing should start low (0.3 to 0.5 mg about 30 minutes to one hour before bed) and increase only if needed. One milligram (mg) tablets can be cut in half to get a 0.5 mg dose, if needed (but do not cut the timed-release product).

Side effects are minimal, but drug interactions may go undetected unless a drug interaction review is performed with all over-the-counter, herbal and prescribed drugs.

Studies looking at long-term use of melatonin, especially in children, are not widely available, raising concerns about use in this population. Always seek a pediatrician's advice before giving melatonin to any child. Undiagnosed sleep disorders in children should always be addressed by your health care provider.

Finished: Melatonin: Worth Losing Sleep Over?

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Further information

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