Melatonin and Over-the-Counter Sleep Aids: What Works

Melatonin has become one of the first things people reach for after a run of bad nights. The share of U.S. adults taking it rose from about 0.4 percent in 1999-2000 to 2.1 percent in 2017-2018, and it sits on the shelf beside “PM” pain relievers, sleep tablets and herbal blends.

So does melatonin for sleep work? Somewhat, for some problems. The evidence is modest and mixed, and much depends on whether your trouble is lying awake or sleeping at the wrong times.

A Clock Signal More Than a Sleeping Pill

Melatonin is a hormone your brain makes in response to darkness. It helps with the timing of your 24-hour internal clock and with sleep. Think of it more as a signal that night has arrived than as a switch that turns you off, although it can make some people drowsy.

In the U.S., melatonin is sold as a dietary supplement, which means it’s regulated less strictly than a prescription or over-the-counter drug.

Ordinary Insomnia: Where the Research Disagrees

Suppose your schedule is normal, but you lie awake most nights. Researchers and guideline writers don’t fully agree on what melatonin offers you.

The case against. The American Academy of Sleep Medicine’s 2017 guideline suggests that clinicians not use melatonin for chronic insomnia. The 2025 guideline from the U.S. Department of Veterans Affairs and Department of Defense also suggests against melatonin and other supplements such as valerian (a weak recommendation), citing very low-certainty evidence, harms that slightly outweighed the benefits, concerns about supplement purity, and the risk of delaying effective treatment. It also suggests against diphenhydramine.

The case for. That 2017 recommendation is labeled weak and rests on three studies, all in adults over 55. A 2013 meta-analysis, which pools results from many studies, combined 19 trials in adults and children with primary sleep disorders, not only adults with ordinary insomnia. People on melatonin fell asleep about 7 minutes sooner and slept about 8 minutes longer than people on a placebo (an inactive pill). The authors called the effects modest but suggested melatonin may still have a role because its side effects appear mild.

Put together, any benefit for falling asleep looks small and uncertain. A 2022 review of adults with chronic insomnia found no significant improvement in how quickly people fell asleep, total sleep or sleep efficiency. Another 2022 review, of adults with a range of health conditions, found some improvement in reported sleep quality, and a 2022 review described by NCCIH found no improvement in sleep quality or time awake during the night. The three studies behind the 2017 guideline also all used prolonged-release melatonin, a prescription medicine in Europe and other countries, so the results may not apply to the gummies and tablets sold as supplements in U.S. stores. Seven minutes can be real in a trial and still go unnoticed at 2 a.m.

Body-Clock Problems: A Better Fit, With Caveats

Melatonin’s case is stronger when the problem is timing, though the evidence still has limits.

• Jet lag. A 2002 Cochrane review found less jet lag in nine of ten trials of flights crossing five or more time zones, with melatonin taken close to bedtime at the destination. The National Center for Complementary and Integrative Health (NCCIH) is more cautious, saying melatonin may help.
• Delayed sleep-wake phase disorder. This means your body naturally falls asleep and wakes very late. For adults, the American Academy of Sleep Medicine gives timed melatonin a weak recommendation, based on low-quality evidence with contradictory results, so the balance of benefits and harms remains uncertain.
• Shift work. A Cochrane review found people may sleep about 24 minutes longer during the day, on low-quality evidence, and the effect was no longer significant once two trials at higher risk of bias were removed. A 2026 American Academy of Sleep Medicine guideline conditionally suggests melatonin for daytime sleep after night shifts, on very low-certainty evidence, and warns that melatonin can leave you sleepy, so allow time for that to wear off before driving or returning to work. Our post on shift work and mood covers what else helps.

When you take it matters, and the right time differs by problem. The jet lag reviewers warned that melatonin taken at the wrong time can cause sleepiness and slow adjustment. Studies disagree on whether larger amounts work better, and some found no added benefit from taking more, so we don’t give amounts here.

What’s Actually in the Bottle

The FDA can’t approve dietary supplements or their labels before they’re sold. Testing suggests that labels can be well off the mark:

• A 2023 JAMA study of 25 melatonin gummy products sold in the U.S. found 22 inaccurately labeled. Actual melatonin ranged from 74 to 347 percent of the labeled amount, and one product had none detectable but did contain CBD.
• A 2017 study of 31 supplements bought in Ontario, Canada, found more than 71 percent were off by over 10 percent. Serotonin turned up in 26 percent.

Short-term use appears to be safe for most people, but information on long-term safety is lacking. NCCIH says people with epilepsy or on blood thinners need medical supervision when taking it, and research in pregnancy and breastfeeding is lacking. Store melatonin, especially gummies, out of children’s reach: reports to U.S. poison centers of children swallowing melatonin rose sharply from 2012 to 2021, with thousands of hospitalizations.

Those “PM” Products Are Antihistamines

Many sleep aids contain diphenhydramine or doxylamine, older antihistamines that cause drowsiness. Sleepiness is easy to get from them. Better sleep is less certain.

• The evidence is thin. The 2017 guideline also suggests against diphenhydramine for chronic insomnia, because the benefits fell below what counts as clinically meaningful. A 2005 trial in mild insomnia found modest improvement, with few differences from placebo reaching statistical significance. On the other side, it saw no significant next-day effects and no rebound insomnia after two weeks of use.
• The effect can fade. In a small study of 15 healthy men taking diphenhydramine during the day, its sedating effect was gone by day four. A label may say “non-habit forming,” but that doesn’t mean a product keeps working. The same label says not to use it with any other product containing diphenhydramine, even one used on the skin.
• Side effects are real. They include dry mouth, dizziness and drowsiness. The “PM” combination labels say not to drive or operate machinery, and in a U.S. driving-simulator study, a standard dose of diphenhydramine impaired driving more than alcohol at a level above the legal limit for driving. With doxylamine, getting up too soon can leave you drowsy.
• Pain-relief versions add a second drug. Using one just for sleep means taking a pain reliever you may not need. Acetaminophen versions carry a liver warning. Ibuprofen and naproxen versions, such as Advil PM and Aleve PM, carry label warnings about stomach bleeding, heart attack and stroke, and say not to use them from 20 weeks of pregnancy on unless a doctor directs it.

Sleep aid labels say to avoid alcohol, and to ask a doctor first if you have glaucoma, a breathing problem or trouble urinating from an enlarged prostate. The American Geriatrics Society advises people 65 and older to avoid these medications, because they’re strongly anticholinergic, are cleared more slowly with age, and lose their sedating effect when used for sleep. It notes that cumulative exposure to this type of drug has been associated with falls, delirium and dementia, “even in younger adults,” based on observational studies.

Herbs, Magnesium and Other Shelf Options

These are popular, and the evidence for them is mostly weak or debated.

• Valerian. This one is debated. A 2006 review suggested it might improve sleep quality, but most of its studies had significant problems. A 2020 review was more favorable. NCCIH calls the evidence inconsistent, and the 2017 guideline suggests against it.
• Magnesium. There’s very little research, and it’s low quality or conflicting.
• Tryptophan. NCCIH warns that L-tryptophan may cause life-threatening serotonin toxicity with medicines that affect serotonin, and the 2017 guideline suggests against it.
• Kava. It’s been linked to liver injury that’s sometimes serious or even fatal.
• CBD. A 2020 review found too little evidence for cannabinoid therapies in any sleep disorder. See our post on cannabis and mental health.
• Alcohol. It’s not an appropriate sleep aid and tends to bring unrefreshing sleep with many awakenings.

If You Take Psychiatric Medication, These Aren’t Neutral

“Natural” and “over the counter” don’t rule out an interaction, so tell your provider about anything you take at night.

• Melatonin and fluvoxamine. In a very small study of healthy volunteers, the antidepressant fluvoxamine raised melatonin levels sharply. Melatonin is broken down mainly by a liver enzyme called CYP1A2, which fluvoxamine blocks, and the same enzyme explains other effects found in small international studies: caffeine and birth control pills raised melatonin levels, and smoking lowered them, as a review of melatonin studies also notes. Check with your provider or pharmacist.
• Tryptophan. Fluvoxamine’s label lists it among the products that can add to the risk of serotonin syndrome, a serious reaction.
• Drowsiness can stack. Sleep aid labels say to ask first if you take sedatives, and some antidepressants may make you drowsy. Drowsiness from melatonin and other sedating medicines can add up, so check with your provider or pharmacist before combining them.

Your medication may also be part of the sleep problem, since antidepressants can interfere with sleep. If you suspect yours is, say so. Please don’t stop a medication on your own; some can cause withdrawal symptoms or a return of symptoms if stopped suddenly.

What Has Stronger Support for Lasting Insomnia

For chronic insomnia, the answer to “what works” mostly isn’t on the shelf. The American College of Physicians recommends cognitive behavioral therapy for insomnia (CBT-I) as the first treatment for adults with chronic insomnia, and NCCIH calls it the most strongly recommended treatment. It asks for several weeks of real effort, and no treatment works for everyone.

Our post on CBT-I explains how it works. Insomnia that started with something else explains why sleep trouble can outlast its cause. We don’t offer standalone weekly therapy, but we’re happy to help you find a therapist and, with your permission, we’ll coordinate with them.

When It’s Time to Stop Troubleshooting Alone

A new product probably isn’t the next step if any of these sound familiar:

• Sleeplessness has lasted more than two weeks. Sleep aid labels say to stop and ask a doctor, because insomnia may be a symptom of a serious underlying illness.
• You need more of a product, or need it every night, to get the same result.
• You snore loudly, or someone has noticed pauses in your breathing. Sleep apnea needs its own evaluation.
• You wake too early and can’t get back to sleep, which may be a sign of depression.
• Low mood, worry or irritability came along with the sleep trouble.
• You feel you barely need sleep. A decreased need for sleep can be a sign of a mood episode in bipolar disorder, so contact a provider promptly.

For adults in South Jersey, our board-certified psychiatric nurse practitioners can look at whether anxiety, depression or a medication is feeding the insomnia, and tell you when it makes sense to see your primary care provider or a sleep medicine provider. Our sleep disorders page covers how sleep and mental health affect each other. Our post on why your sleep may be affecting your mental health goes further, and if you’re not sure where to begin, start with “I can’t sleep.”

Frequently Asked Questions

Does melatonin actually help you sleep?

It may help a little. In pooled trials, people fell asleep about 7 minutes sooner and slept about 8 minutes longer than on a placebo. Two U.S. guidelines suggest against it for chronic insomnia. It has a better case for jet lag and a delayed body clock, though that evidence has limits too.

Is it safe to take melatonin every night?

Short-term use appears to be safe for most people, but long-term safety hasn’t been established. Products may also not contain what the label says. If you’ve been taking it for a long time, mention it to your provider, especially if you have epilepsy, take a blood thinner or are pregnant.

Is it safe to take Benadryl for sleep every night?

Nightly use isn’t a good long-term plan. Benadryl contains diphenhydramine, and sleep aid labels with this ingredient say to stop and ask a doctor if sleeplessness lasts more than two weeks. Its effect may also fade with repeated use, and a guideline suggests against it for chronic insomnia.

Can I take melatonin with an antidepressant?

Ask your provider or pharmacist first, because it depends on the medication. Fluvoxamine, for example, raised melatonin levels sharply in a very small study. Bring a list of everything you take, including supplements.

What’s the best over-the-counter sleep aid?

No product has strong evidence for chronic insomnia. A U.S. sleep medicine guideline suggests against melatonin, diphenhydramine and valerian for it. For jet lag, melatonin has some support. For insomnia that keeps going, CBT-I has the strongest backing.

If sleep aids have become part of your nightly routine, a psychiatric evaluation can help sort out what’s driving the problem, and medication management gives you regular follow-ups to review everything you take.

This article is for general educational purposes only. It does not constitute medical advice, does not establish a provider-patient relationship, and is not a substitute for individual evaluation, diagnosis, or treatment by a qualified clinician. If you’re in crisis or thinking about harming yourself, call or text 988 (Suicide & Crisis Lifeline), any time, day or night. In an emergency, call 911 or go to the nearest emergency room.