22/01/2025
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Melatonin is an oral, over-the-counter (OTC) dietary supplement available without a prescription in the U.S. It is often used to help with jet lag or trouble sleeping and comes as tablets, capsules, an oral liquid and chewable gummies.
Melatonin is also a natural hormone your body secretes in response to darkness to help maintain your wake-sleep cycle (also called “biological clock”). The wake-sleep cycle is the process of sleep and wakefulness; in humans this averages 8 hours of nighttime sleep and 16 hours of daytime activity.
Natural melatonin levels usually peak between 11PM and 3AM. Nighttime levels are roughly 10 times higher than in the daytime. Levels fall sharply before daylight, and are barely detectable in the daylight hours. The rise and fall in natural levels signal wake and sleep times, known as our circadian rhythm.
Shorter periods of natural melatonin production occur in the summer with longer days, and longer periods of production occur in the winter. Light at night (such as from smartphones or the TV) blocks production and can lead to sleep disturbances. Age also lowers nighttime melatonin release, which may contribute to the problem of insomnia and early awakening often seen in older adults.
What is melatonin used for?
Melatonin is most commonly used to treat:
insomnia (trouble sleeping)
jet lag due to travel
sleep cycles in the blind (non 24-Hour Sleep Wake Disorder)
shift-work sleep disorders in people with alternating work schedules
Melatonin dietary supplements may be promoted for many other uses, from eczema, to bowel disorders to cancer treatment, but adequate studies are lacking. It has been widely studied for treatment of jet lag and other sleep disorders.
How does melatonin work?
Natural melatonin is a hormone produced in the pineal gland in the brain. It is made from the amino acid tryptophan and then released into the blood and cerebrospinal fluid, crossing into the brain. It sends messages to areas in the brain and body to help control the sleep and wake cycles.
When taken as a dietary supplement, its function is to act like the natural sleep hormone. Drowsiness generally occurs within 30 minutes after taking a dose.
Taking supplemental melatonin for sleep before bedtime may not be the best strategy for all sleep disorders and may not work for everyone. Trouble with sleep may be a symptom of other medical disorders, like depression, anxiety or sleep apnea, so check with your doctor if your insomnia persists. Also check with a child's doctor before use.
Is melatonin a hormone or a vitamin?
Melatonin is a natural hormone when produced in the body and is not a vitamin. Melatonin supplements you take by mouth - like pills, liquids or chewable gummies - are man-made products available without a prescription at the pharmacy, nutrition stores, and other retail shops.
Before taking this medicine
Do not use melatonin if you are allergic to it.
Before using this medication or giving it to your child, talk to your healthcare provider. This medication may not be recommended if you have certain medical conditions, such as:
diabetes
depression
a bleeding or blood clotting disorder such as hemophilia
taking a blood thinner like warfarin
high or low blood pressure
epilepsy or other seizure disorder
if you are using any medicine to prevent organ transplant rejection
an autoimmune condition
using other sedatives or tranquilizers
It is not known whether this medication will harm an unborn baby. Do not use this product without medical advice if you are pregnant.
High doses of this medicine may affect ovulation, making it difficult for you to get pregnant.
It is not known whether melatonin passes into breast milk or if it could harm a nursing baby. Do not use this product without medical advice if you are breast-feeding a baby.
Do not give any herbal or dietary supplement to a child without medical advice from a qualified healthcare provider.
Melatonin dosage
Melatonin is considered an effective short-term treatment for jet lag and may aid with sleep during times when you would not normally be awake.
Effective starting doses of melatonin for jet lag range from 0.3 to 0.5 mg. One milligram tablets can be cut in half to achieve a 0.5 mg dose of melatonin if smaller doses are not available for purchase. Higher doses are commonly marketed in the U.S. (up to 10 mg), but higher doses may be associated with more side effects such as headache, next day drowsiness, or vivid dreams. Side effects of melatonin may occur more frequently or worsen in older adults.
Always start with the lowest dose. According to a Cochrane review, doses over 5 mg appear to be no more effective than lower doses. Higher doses may result in excessively high levels of physiologic melatonin.
Melatonin for jet lag
Jet lag is an air travel problem that causes trouble with falling and staying asleep, fatigue, trouble concentrating, constipation, and other symptoms. Jet lag is much more likely if you cross over several time zones, and can worsen the more time zones you cross.
Effective starting doses for jet lag range from 0.3 to 0.5 mg. Smaller doses may work for some while others may need a higher dose. It may be more difficult to fly east, when time is lost, rather than to fly west, when you gain it back. High doses, such as 20 mg pills are available for purchase on the Internet, but such high doses are not normally recommended or needed, and may greatly increase side effects.
Eastbound: If you are traveling east, say from the US to Europe, take supplemental melatonin for sleep after dark, 30 minutes before bedtime in the new time zone or if you are on the plane. Then take it for the next 4 nights in the new time zone, after dark, 30 minutes before bedtime. If you are still feeling drowsy the day after using this medication, try a lower dose.
Westbound: If you are heading west, for example, from the US to Australia, a dose is not needed for your first travel night, but you then may take it for the next 4 nights in the new time zone, after dark, 30 minutes before bedtime. Melatonin may not always be needed for westbound travel.
Given enough time (usually 3 to 5 days), jet lag will usually resolve on its own, but this is not always optimal when traveling.
Melatonin for sleep disorders
Primary Sleep Disorders (Insomnia):
Dosage: Take 0.1 mg to 0.5 mg thirty minutes before bedtime. Studies suggest supplemental melatonin for primary sleep disorders may be effective in promoting but not maintaining sleep (early morning awakening). It is not usually recommended for long-term use. If insomnia continues, seek the advice of a healthcare provider.
Shift-Work Sleep Disorders
Dosage: Take 1 to 3 mg thirty minutes prior to the desired onset of daytime sleep; melatonin may NOT lead to improved alertness during the nighttime work shift.
Delayed Sleep-Wake Phase Disorder
Delayed sleep-wake phase disorder (DSWPD) most often occurs in adolescents, possibly due to reduced production and melatonin deficiency at this age. Sleep onset is delayed by 3 to 6 hours compared with conventional bedtimes (10 to 11 pm). DSWPD can negatively affect school performance, daily activities, and lead to morning drowsiness which can be dangerous for teen drivers. Any sleep disorder in an adolescent should be evaluated by a physician.
Dosage: No consensus is available for dosing in DSWPS. Some clinicians recommend 3 to 5 mg taken in the early evening, at least 1.5 hours before the desired bedtime. Bright light therapy and behavioral management may enhance results. Be aware drowsiness may occur after the melatonin dose, so avoid hazardous activities such as driving.
Non-24-Hour Sleep Wake Disorder (Non-24)
More than 70% of people who are totally blind have Non-24, a circadian rhythm disorder. For people who are totally blind, there are no light cues to help reset the biological clock. The sleep time and wake up time of people who have Non-24-Hour Sleep Wake Disorder shifts a little later every day. Sleep times go in and out of alignment compared to a normal sleep-wake phase. Extra minutes add up each day by day and disrupt the normal wake-sleep pattern.
Use of melatonin in Non-24 is to aid in stimulation to reset the biological clock with one long sleep time at night and one long awake time during the day.
Dosage: Studies on people who are the blind suggest 0.5 mg/day, taken either at a fixed time before bed or one hour before bedtime.
Hetlioz, a prescription-only melatonin agonist is approved for use in Non-24-Hour Sleep Wake Disorder in adults and for the treatment of Nighttime Sleep Disturbances in Smith-Magenis Syndrome (SMS) in patients 3 years of age and older.
Hetlioz (tasimelteon)
Rozerem (ramelteon), also a melatonin agonist, has been approved to treat insomnia characterized by difficulty with sleep onset in adults.
Hetlioz (tasimelteon)
Rozerem (ramelteon)
Fast-dissolving Tablets
Some melatonin tablets are available in fast-dissolving formulations in the U.S. To take the orally disintegrating tablet:
Use dry hands to remove the tablet and place it in your mouth.
Do not swallow the tablet whole. Allow it to dissolve in your mouth without chewing. If desired, you may drink liquid to help swallow the dissolved tablet.
Melatonin for Children
Parents may consider using melatonin to help their child who has a trouble falling asleep. Only use this medication for your child under the care of a pediatrician or other medical sleep specialist. Insomnia or other sleeping disorders in children should always be evaluated by a medical professional.
Melatonin should not be used as a substitute for good sleep hygiene and consistent bedtime routines in children. According to Yale sleep specialist Dr. Craig Canapari, use of this medication results in less difficulty with falling asleep, earlier time of sleep onset, and more sleep at night.
Products containing lower-dose melatonin for kids do exist on the U.S. market. Long-term use of this medication has not been studied in clinical trials for children and possible side effects with prolonged use are not known. The use of melatonin in children with autism spectrum disorder or attention-deficit hyperactivity disorder should involve behavioral interventions and should be directed by a physician.
Delayed sleep phase disorder often occurs in teenagers and young adults, possibly due to alterations in endogenous production. Sleep onset is delayed by 3 to 6 hours compared with normal bedtime hours of 10 to 11 PM. Maintaining a consistent bedtime free of electronics for at least one hour prior to bedtime is especially important for insomnia in children and adolescents.
Melatonin Side Effects in Children
The most common melatonin side effect in children is morning drowsiness. Other common side effects in children include:
Bedwetting
Headache
Dizziness
Nausea
Diarrhea
Possible increased risk for seizures in children with severe neurological disorders.
Dietary melatonin supplements can still have drug interactions or health risks if you have certain medical conditions, upcoming surgery, or other health concerns.
Is Melatonin Safe?
Melatonin is a relatively safe supplement when used in the short-term, and melatonin side effects are uncommon. Its safety in the long-term has not been determined in randomized, controlled studies. In general this medication appears to be relatively nontoxic, even at higher doses such as 3 to 5 mg once a day.
Some people can have side effects from melatonin that may include:
daytime drowsiness, dizziness, weakness, or confusion
vivid dreams, nightmares
feeling depressed, anxious, irritable
headache
loss of appetite, diarrhea, nausea, stomach pain
blood pressure changes
joint or back pain
elevated risk for seizures
Higher external doses(>1 mg to 10 mg) can worsen side effects like daytime drowsiness, impaired physical or mental ability, low body temperature, and elevated prolactin levels.
Melatonin Reviews and Studies
For Primary Sleep Disorders
Researchers have conducted many studies on melatonin supplements for various health conditions. Most studies have been conducted in sleep disorders, such as jet lag, shift work sleep disorders, delayed sleep phase disorder, and insomnia. Studies are often not consistent in their results and questions still remain about its usefulness, dosage, length of treatment and long-term safety for some sleep conditions.
Melatonin can be effective for jet lag for many people when dosed at the appropriate time. Studes measuring the effectiveness of melatonin for the treatment of insomnia show a slight reduction in the amount of time needed to fall asleep, but melatonin may not increase the overall quality of sleep. This medication does appear to be safe for short-term use for primary insomnia (less than three months).
For Other Conditions
Multiple areas for melatonin use have been investigated, but not all uses may be accepted or have adequate research to determine appropriate clinical use. These include:
Cancer
Boost the immune system
Sunburn
Irritable Bowel Syndrome (IBS)
Fibromyalgia
Systemic sclerosis
Antioxidant and free radical scavenger
Alzheimer’s disease
Ocular diseases
Sleep aid for children with autism spectrum disorder or attention deficit hyperactivity disorder (ADHD)
Amyotrophic lateral sclerosis (ALS)
Nighttime blood pressure control
Seasonal affective disorder (SAD
How Does Melatonin Come at the Store?
In the U.S., melatonin pills can be purchased without a prescription in the pharmacy, grocery, or health food store. Pill strengths range from 1 milligram (mg) to 10 mg, but you should always start with the lowest dose to judge its effects. Some experts suggest to start with 0.3 to 0.5 mg thirty minutes before bedtime, instead of the higher doses. Cut a 1-mg immediate release tablet in half to get a 0.5 mg dose if lower doses are not available; don’t do this with time release products. Also, don't drink alcohol with the time-release preparation, as it can disrupt the time-release mechanism.
Does Food Contain Melatonin?
A study published in Food and Nutrition Research notes that certain food products do contain various amounts of melatonin as measured by immunological and chromatographic laboratory techniques. How consumption of these various foods might affect endogenous production sleep or was not evaluated:
Tomatoes
Walnuts
Rice/barley cereal
Strawberries, tart cherries
Olive oil
Wine, beer
Cow’s milk
Research finds that melatonin synthesis depends upon availability of the essential amino acid tryptophan, a needed component of the diet. If intake of tryptophan is severely restricted, synthesis of melatonin is significantly reduced in humans.
In the Nurses’ Health Study, no link was found between the consumption of various nutrients, such as folate, vitamin B6 and zinc and increased urinary excretion.
Diets rich in vegetables, fruits and grain products will contain considerable levels of dietary melatonin. The overall effect of dietary consumption on nighttime levels of melatonin is very limited. Melatonin production is primarily driven by the effects of light and darkness and by age, declining as we get older.
