How Much Melatonin Should You Take? Usually Less Than the Bottle Says
Most adults who use melatonin need far less than the 5–10 mg on many labels. Start with 0.5–1 mg, 1–2 hours before bed, for short stretches. Doses above 5 mg did no better for jet lag in a Cochrane review. A 2025 heart study linked a year or more of use to heart failure, but it was a preliminary, observational abstract that cannot show cause.
How much melatonin should I take?
For most adults, 0.5 to 1 mg is enough to start. Low doses worked in trials, and in a jet-lag review doses above 5 mg worked no better. Timing matters as much as dose. Use it for weeks, not years, and ask a doctor first if you take other medicines.
Try 0.5–1 mg, 1–2 hours before bed, for up to a few weeks.
Take 0.5–5 mg near bedtime at your destination, for a few nights.
You probably don't need it. Keep your wake-up time fixed instead.
Ask your doctor; the UK prescribes 2 mg slow-release for this.
Talk to your pediatric clinician before giving any melatonin.
On Sunday, November 1, 2026, at 2:00 a.m., most of the US sets its clocks back one hour. For many people, that week means a bottle of melatonin on the nightstand. It is also a year after the American Heart Association heard a study that linked long-term melatonin use to a higher risk of heart failure. That result made headlines, though it was preliminary.
So the question people ask is simple: how much should I take, and is it safe? The research gives a clear answer on dose and a more cautious one on safety. Most people take more than they need. Labels are often wrong. And melatonin works best as a signal to your body clock, not as a sleeping pill. This guide explains the new heart study, how melatonin works, what the trials show, how much to take and when, how accurate labels are, who should be careful, and when to see a doctor.
What's New: The Melatonin Heart Failure Study
A 2025 study of 130,828 adults with insomnia linked a year or more of prescribed melatonin to a higher rate of heart failure (HR 1.89). It was an abstract, not a peer-reviewed paper, and it cannot show that melatonin caused it.
The study. Ekenedilichukwu Nnadi, MD, a chief resident in internal medicine at SUNY Downstate and Kings County Primary Care in Brooklyn, presented the work at the American Heart Association's Scientific Sessions in New Orleans in November 2025. The team used TriNetX, a large network of electronic health records. They found 130,828 adults with insomnia and no prior heart failure. Of these, 65,414 had melatonin recorded in their charts for 12 months or more. They were matched with 65,414 people who did not, on 40 factors such as age, sex and other health conditions. People taking other prescription sleep drugs were excluded.
The finding. Over five years, 4.6% of melatonin users developed heart failure, compared with 2.7% of non-users. That is a hazard ratio of 1.89, or roughly 90% higher risk. Users were also hospitalized for heart failure more often and were more likely to die from any cause:
Melatonin supplements may not be as harmless as commonly assumed.
What the study can't tell you. The AHA itself listed the limits. This was a research abstract, which is preliminary and not peer-reviewed. The data are observational, so they show a link, not a cause. People were counted as users only if melatonin appeared on a prescription. In countries like the US, where melatonin is sold over the counter, many people in the “non-user” group may have been taking it. The records had no information on dose or on how severe each person's insomnia was. People who get a prescription for a sleep aid may simply be sicker to begin with.
What other experts said. Sleep specialist Sujay Kansagra of Duke University told CNN the study left him “with a lot more questions than answers.” He suggested melatonin may be an “innocent bystander” to the poor sleep and health problems that come with chronic insomnia. As of October 2026, we found no peer-reviewed version of the paper in PubMed.
Our read. The study does not prove that melatonin harms the heart. It does give a good reason not to take it every night for years without a doctor's advice. That fits with how the UK prescribes it: for adult insomnia, usually for up to 13 weeks.
How Melatonin Works: A Clock Signal, Not a Sedative
Your brain makes melatonin when it gets dark. It tells your body clock that night has started. In a 2001 trial, 0.3 mg was enough to restore normal nighttime levels.
Melatonin is a hormone made by the pineal gland, a small gland deep in the brain. Light suppresses it. Darkness lets it rise in the evening, and it stays high through the night. It doesn't knock you out. It tells the rest of your body that it is night, which makes sleep easier to start.
Releases melatonin in the dark; light switches it off.
Reads the signal as “night has started” and shifts toward sleep.
Why small doses can be enough. In a 2001 trial at MIT, led by Irina Zhdanova and Richard Wurtman, adults over 50 with insomnia took 0.3 mg or 3 mg at bedtime. The 0.3 mg dose restored normal nighttime blood levels and improved how efficiently they slept. The 3 mg dose pushed blood levels well above normal, and they stayed high into the daytime. It also lowered body temperature. An earlier 1995 trial by the same group found that 0.3 or 1 mg shortened the time it took to fall asleep, with no next-day hangover.
A dose that leaves melatonin in your blood after you wake up can work against you. It sends a “night” signal at the wrong time. That is one reason more is not better.
Does Melatonin Work for Sleep?
Modestly. A meta-analysis of 19 trials found people fell asleep about 7 minutes faster and slept about 8 minutes longer. The AASM suggests not using it for chronic insomnia.
The best summary. A 2013 meta-analysis in PLoS One by Eduardo Ferracioli-Oda, Ahmad Qawasmi and Michael Bloch at Yale pooled 19 randomized controlled trials with 1,683 people who had primary sleep disorders. Compared with placebo, melatonin shortened the time to fall asleep and slightly lengthened total sleep:
To put that in context, seven minutes is real but small. The authors also found a modest improvement in how people rated their sleep quality. That is consistent with a nudge to the body clock, not a sedative effect.
What the guideline says. The American Academy of Sleep Medicine's 2017 guideline on chronic insomnia in adults is blunt: “We suggest that clinicians not use melatonin as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults.” It rated that suggestion as weak, which means the evidence was limited, not that melatonin is harmful.
Where it works best. Melatonin is most useful when the body clock is out of step with the clock on the wall. That includes jet lag and delayed sleep timing, when someone can't fall asleep until very late. A 2002 Cochrane review of 10 trials found that melatonin reduced jet lag, with a number needed to treat of 2. In other words, about one in two travelers who took it felt better than they would have without it.
The evidence has limits. Trials are small and use different doses, timings and products. A 2024 dose-response meta-analysis of 26 trials, by Francy Cruz-Sanabria and colleagues in the Journal of Pineal Research, found that the effect on falling asleep peaked at about 4 mg a day. Comparing across trials, it also suggested that taking melatonin about 3 hours before the desired bedtime might work better than the common 30 minutes, though no trial tested that head to head. So low doses are a sensible start, but some people may need a little more.
How the evidence stacked up
- 1995 · Trial, MIT
0.3 or 1 mg shortened the time to fall asleep, with no hangover.
- 2001 · Trial, adults over 50
0.3 mg restored normal night levels; 3 mg lingered into the day.
- 2002 · Cochrane review, 10 trials
0.5–5 mg eased jet lag; above 5 mg was no better.
- 2013 · Meta-analysis, 19 trials
Sleep came 7.06 minutes sooner; total sleep rose 8.25 minutes.
- 2017 · AASM guideline
Suggests not using melatonin for chronic insomnia (weak).
- 2024 · Dose-response meta-analysis, 26 trials
Effect on falling asleep peaked at about 4 mg.
- 2025 · AHA abstract, 130,828 adults
Long-term use linked to heart failure; cause not shown.
How Much Melatonin Should You Take?
Start with 0.5–1 mg. If that doesn't help after a week or two, up to 3 mg is reasonable. For jet lag, doses above 5 mg worked no better.
There is no single official dose for adults in the US, because melatonin is sold as a dietary supplement and isn't approved by the FDA as a sleep drug. Elsewhere, regulators have set clear numbers. In the EU, a product may claim to help you fall asleep faster only if it provides 1 mg taken close to bedtime. For jet lag, the EU claim starts at 0.5 mg. In the UK, melatonin is prescription-only. The NHS standard for short-term insomnia in people aged 55 and over is one 2 mg slow-release tablet taken 1 to 2 hours before bedtime.
US use has grown fast. A 2022 research letter in JAMA found that the share of adults taking melatonin rose from 0.4% in 1999–2000 to 2.1% in 2017–2018. The share taking more than 5 mg a day more than tripled, from 0.08% to 0.28%.
Close to the 0.3 mg that restored normal nighttime levels in a 2001 trial, and the lowest dose in the EU jet-lag claim. Our suggested start.
The dose behind the EU claim that melatonin helps you fall asleep faster, taken close to bedtime. Also a sensible start.
The NHS standard tablet for jet lag, for up to 5 days. In a 2001 trial, 3 mg kept blood levels raised into the daytime.
The top of the range the Cochrane review found useful for jet lag. Doses above 5 mg worked no better.
Twice the useful ceiling for jet lag, with no extra benefit shown. A common label strength in US stores.
| Dose | Where the number comes from |
|---|---|
| 0.3 mg | Restored normal nighttime levels in adults over 50 (2001 trial) |
| 0.5 mg | Lowest dose in the EU jet-lag claim; shifted the body clock as well as 3 mg when well timed (2010 trial) |
| 1 mg | EU claim for falling asleep faster, taken close to bedtime |
| 2 mg slow-release | NHS prescription for insomnia, age 55+, usually for up to 13 weeks |
| 3 mg | NHS standard tablet for jet lag, for up to 5 days |
| About 4 mg | Where the effect on falling asleep peaked (2024 meta-analysis) |
| 5 mg | Top of the useful range for jet lag; higher doses were no better (Cochrane) |
Start at 0.5–1 mg, 1–2 hours before bed. Stay at or below 5 mg, and use it for weeks, not years.
Low doses are backed by trials, cheap and less likely to leave you groggy. If 1 mg does nothing after a week or two, trying 3 mg is reasonable. Going above 5 mg added no benefit for jet lag, and big doses only raise the gap between what the label says and what may be inside. If you still need help after a few weeks, the problem is probably not a lack of melatonin, and a clinician is the better next step.
What's Really in a Melatonin Bottle
Labels are often wrong. In a 2017 study, products held from 83% less to 478% more melatonin than stated. Look for a USP Verified seal.
Three studies, one message. In 2017, Lauren Erland and Praveen Saxena at the University of Guelph tested 31 melatonin supplements sold in Canada. Content ranged from 83% below to 478% above the label. More than 71% were off by more than 10%. Different lots of the same product varied by up to 465%. Eight products also contained serotonin, a related compound that was not on the label.
In 2023, Pieter Cohen and colleagues tested 25 melatonin gummy products sold in the US and reported the results in JAMA. Gummies held 74% to 347% of the labeled amount, and 22 of the 25 were mislabeled. One product contained no melatonin at all, but did contain 31.3 mg of CBD. A 2024 survey by FDA scientists of 110 products marketed for children found content from 0% to 667% of the label.
That spread is the hidden reason to keep doses low. If you buy a 10 mg product and the content runs high, you could be taking several times the dose that was studied. A third-party seal, such as USP Verified, means an independent lab has checked that the bottle matches its label. The AASM recommends choosing such a product.
When to Take Melatonin, by Goal
For sleep, 1–2 hours before bed. For jet lag, near bedtime at your destination. For the November 1 clock change, most people don't need it.
Timing decides what melatonin does. Taken in the evening, it nudges your body clock earlier. Taken at the wrong time, it can push the clock the wrong way. A 2010 trial by Helen Burgess and colleagues in Chicago found that 0.5 mg and 3 mg shifted the clock by similar amounts when each was taken at its best time, in the afternoon or early evening. Pick your goal:
The NHS gives its 2 mg tablet 1 to 2 hours before bedtime. The 2024 meta-analysis suggested that about 3 hours before bed may work better than 30 minutes. Keep the same time every night, and keep lights low afterward.
The Cochrane review found 0.5–5 mg effective when taken close to the target bedtime at the destination (10 p.m. to midnight), for a few days. Taking it too early in the day can delay adjustment. Jet lag is usually worse flying east and across five or more time zones.
On November 1 the clocks move back one hour, so the evening feels later and the morning comes earlier by the body's clock. We found no trial of melatonin for this one-hour shift. The AASM's advice: go to bed at your usual bedtime and wake up at your standard wake time.
A word on the clock change. In a 2024 position statement, the AASM argued that the US should end seasonal clock changes in favor of permanent standard time. The November change is the easier of the two for most people because it gives an extra hour. Its practical advice for the change is to go to bed at your usual bedtime and wake up at your standard wake time. If you already use melatonin for sleep, keep taking it at the same time on the new clock. If you don't, there's no evidence that starting for this week helps. For more on the change, see our guide to adjusting your sleep when the clocks fall back.
Which Melatonin Approach Is Right for You?
Healthy adult who sometimes can't switch off at night.
Try 0.5–1 mg, 1–2 hours before bed, on the nights you need it, for no more than a few weeks. Choose a USP Verified product. If you still struggle after a few weeks, stop and look at your schedule, light and caffeine first. See a doctor if poor sleep lasts for months or affects your days.
Methods to fall asleep faster without medication.You cross several time zones a few times a year.
Take 0.5–5 mg close to your target bedtime at the destination, for the first few nights. Don't take it earlier in the day, which can slow adjustment. Ask your doctor first if you take blood thinners or medicine for epilepsy.
Adult over 55 with ongoing insomnia.
In the UK this group gets a prescription for 2 mg slow-release melatonin, 1 to 2 hours before bed, usually for up to 13 weeks. Talk to your doctor before you start. Cognitive behavioral therapy for insomnia (CBT-I) is the first-line treatment in most guidelines, and it lasts longer than any pill.
You have heart disease, take blood thinners or have epilepsy.
Talk to your doctor before taking melatonin. NIH's complementary health center says people with epilepsy and those on blood thinners need medical supervision. Given the 2025 heart study, anyone with heart failure or at high risk should also ask first. Don't stop a prescribed medicine on your own.
Pregnant or breastfeeding.
There is little research on melatonin's safety in pregnancy or while breastfeeding. Avoid it unless your obstetric provider recommends it, and ask about other ways to manage sleep.
You've taken melatonin every night for a year or more.
You don't need to panic over one abstract. But it's a good moment to review. Ask your doctor whether you still need it, whether a lower dose would do, and whether an underlying sleep problem, such as sleep apnea, has been missed.
Sleep supplements that aren't melatonin, and what the evidence says.Melatonin and Children: Treat It Like a Medicine
Poison-center calls about children swallowing melatonin rose 530% from 2012 to 2021. Keep it locked away and talk to a pediatric clinician before giving it.
Gummies look and taste like candy, and that has consequences. A 2022 CDC report by Karima Lelak and colleagues counted 260,435 calls to US poison centers about children swallowing melatonin from 2012 to 2021. Yearly calls rose from 8,337 to 52,563. Most were accidental, and most involved children aged 5 or younger.
Of those calls, 287 children needed intensive care, and two deaths were reported. A second CDC report in 2024 estimated about 10,930 emergency department visits for unsupervised melatonin ingestion by children aged 5 and under from 2019 to 2022. Gummies accounted for nearly half of them.
The AASM's 2022 health advisory says “melatonin should be handled as any other medication and kept out of reach of children.” It asks parents to talk with a pediatric clinician before giving melatonin, and notes that “many sleep problems can be better managed with a change in schedules, habits, or behaviors rather than taking melatonin.”
Practical Tips for Taking Melatonin
Start at 0.5–1 mg.
Low doses are backed by trials and are less likely to leave you groggy. Split a tablet or buy a low-dose product rather than starting at 5 or 10 mg.
Take it 1–2 hours before bed.
Same time every night. Dim the lights afterward; bright light switches your own melatonin off.
Use it for weeks, not years.
The NHS usually prescribes it for adult insomnia for up to 13 weeks. If you still need it after a few weeks, talk to a clinician about the cause.
Pick a USP Verified product.
Independent tests found labels off by up to several hundred percent. A third-party seal is the simplest check.
Lock it away from children.
Treat it like any medicine. Gummies accounted for nearly half of young children’s ER visits for melatonin.
Fix the schedule first.
A fixed wake-up time, morning daylight and less caffeine late in the day often help more than any supplement.
Common Misconceptions About Melatonin
Melatonin is a sleeping pill.
True or not? Tap to find outHere’s what the evidence says
Not really. It is a signal to your body clock. In a meta-analysis of 19 trials it helped people fall asleep about 7 minutes faster. That is useful for jet lag or a shifted schedule, not a knockout.
If 3 mg doesn’t work, take 10.
True or not? Tap to find outHere’s what the evidence says
It doesn’t work that way. For jet lag, doses above 5 mg were no better than 0.5–5 mg. Higher doses can keep melatonin in your blood into the morning.
It’s natural, so it’s safe for kids.
True or not? Tap to find outHere’s what the evidence says
Not without a clinician. Poison-center calls about children swallowing melatonin rose 530% from 2012 to 2021, and the AASM says to treat it like any other medicine.
The heart study proves melatonin causes heart failure.
True or not? Tap to find outHere’s what the evidence says
It doesn’t. It was a preliminary abstract with observational data, and it could not account for over-the-counter use or dose. It is a reason for caution with long-term use, not proof of harm.
The label tells you the dose.
True or not? Tap to find outHere’s what the evidence says
Often it doesn’t. Gummies tested in 2023 held 74% to 347% of the labeled amount. A USP Verified seal is the best guide.
When to See a Doctor
Melatonin's common side effects in short-term studies are mild: headache, dizziness, nausea and sleepiness. See a clinician promptly if you have:
- Sleep trouble that lasts for months or makes it hard to work, drive or concentrate during the day.
- Signs of a sleep disorder: loud snoring, gasping or pauses in breathing at night, an urge to move your legs in the evening, or falling asleep suddenly during the day.
- Heart symptoms: shortness of breath, swollen ankles or legs, or a racing or irregular heartbeat, especially if you take melatonin regularly.
- Other medicines or conditions: blood thinners, epilepsy, pregnancy or breastfeeding, or dementia in an older relative.
- A child who swallowed melatonin and is unusually sleepy, vomiting or acting differently. Call Poison Help at 1-800-222-1222.