For most adults, 0.5 to 5 mg of melatonin is considered safe for short-term use, with many sleep experts recommending you start at just 1 mg. The ceiling most doctors reference is 10 mg per day, but higher doses don’t necessarily work better and often cause more side effects. The right amount depends on your age, what medications you take, and why you’re using it.
Starting Dose for Adults
Cleveland Clinic recommends starting at 1 mg, then increasing by 1 mg each week until you fall asleep faster, up to a maximum of 10 mg. But “maximum” doesn’t mean “ideal.” Research consistently shows that lower doses, often between 0.5 and 3 mg, are enough to shift your sleep timing without flooding your body with far more melatonin than it naturally produces. Your pineal gland releases roughly 0.1 to 0.3 mg of melatonin per night on its own, so even a 1 mg supplement is several times your natural level.
Take your dose 30 to 60 minutes before bed. Melatonin is absorbed quickly, with blood levels peaking about an hour after you swallow it, and its half-life is short: levels drop by half within 20 to 50 minutes. That fast clearance is why timing matters more than dose size for most people.
Why More Isn’t Better
It’s a common assumption that doubling the dose will make you twice as sleepy. That’s not how melatonin works. At higher doses, your melatonin receptors can become desensitized, essentially tuning out the signal you’re trying to send. A systematic review of studies in older adults found that doses above 6 mg showed no significant sleep improvement compared to placebo, while doses between 0.5 and 6 mg did help.
Higher doses also bring more side effects. At lower amounts, the most common complaints are mild drowsiness and headaches. As you increase the dose, people report nausea, vomiting, dizziness, vivid nightmares, confusion, irritability, nighttime waking, and even bedwetting. The goal is to nudge your body’s sleep signal, not overwhelm it.
Doses for Older Adults
As you age, your body produces less melatonin naturally, which is one reason sleep patterns shift in later years. That might seem like a reason to take more, but the opposite is true. Older adults metabolize melatonin more slowly, so a given dose lingers longer and hits harder.
The European Food Safety Authority recommends 0.3 to 1 mg for older adults. Even on the higher end, 0.5 to 3 mg is a reasonable range for most people over 65. Starting at the lowest dose available and adjusting slowly is especially important in this age group, particularly because melatonin can interact with blood pressure medications and blood thinners, both of which are common in older adults.
Doses for Children
Most children who benefit from melatonin, including those with ADHD, don’t need more than 3 to 6 mg. The American Academy of Pediatrics advises starting at 0.5 to 1 mg, given 30 to 90 minutes before bedtime, and only after discussing it with a pediatrician. Many kids respond well to that low starting dose and never need to increase it.
Safety data for children is limited, especially for long-term use. Short-term studies suggest it’s relatively well tolerated, with morning sleepiness, drowsiness, and increased nighttime urination as the most common side effects. The bigger concern is what happens over years of use. Because melatonin is a hormone, there are theoretical concerns about its effect on puberty. A few long-term observational studies found no clear impact on pubertal development after two to four years, but one study flagged a potential delay after more than seven years of use. The evidence is too thin to draw firm conclusions either way.
Accidental overdoses in children are a real problem. Between 2012 and 2021, poison control centers received more than 260,000 reports involving children and melatonin. Store it out of reach, just as you would any medication.
Pregnancy and Breastfeeding
There isn’t enough safety data to establish a recommended dose during pregnancy. If you’re pregnant or become pregnant while taking melatonin, it’s worth discussing with your doctor whether to continue. Breast milk naturally contains small amounts of melatonin, and the amount that passes through from a supplement is thought to be low. The main risk is that it could make your baby unusually sleepy or affect feeding. If you’re breastfeeding and taking melatonin, avoid sharing a bed with your baby, since the sedative effect on you increases the risk.
Medication Interactions to Watch
Melatonin is not as harmless to combine with other drugs as many people assume. It can increase bleeding risk when taken with blood thinners. It may interfere with blood pressure medications, potentially worsening blood pressure control. If you take diabetes medications, melatonin can affect blood sugar levels in ways that complicate management.
Combining melatonin with any sedative, including alcohol and sleep medications, can stack the drowsiness effect beyond what’s safe. It may also reduce the effectiveness of anti-seizure drugs, which is a particular concern for children with neurological conditions. People on immunosuppressants should be cautious, because melatonin can stimulate immune function and work against those drugs. One antidepressant, fluvoxamine (commonly prescribed for OCD), dramatically increases melatonin levels in the blood and can cause excessive drowsiness if the two are combined.
The Label Problem
One of the biggest safety issues with melatonin has nothing to do with the dose you choose. Because melatonin is sold as a dietary supplement in the United States, it isn’t regulated by the FDA the way medications are. A study highlighted by the American Academy of Sleep Medicine found that more than 71 percent of melatonin supplements didn’t contain what the label claimed, even within a 10 percent margin of error. Actual melatonin content ranged from 83 percent less than stated to 478 percent more. Even different bottles of the same product varied by as much as 465 percent between manufacturing batches.
Some products tested also contained unlisted ingredients like serotonin or CBD. This means that when you take “3 mg” of melatonin, you might actually be getting anywhere from 0.5 mg to over 14 mg, with no way to know from the packaging. Choosing products that carry a third-party testing seal (such as USP or NSF) improves your odds of getting what you expect.
Practical Approach to Finding Your Dose
Start with the lowest dose you can find, ideally 0.5 to 1 mg, taken about 30 to 60 minutes before your target bedtime. Give it a full week before deciding it isn’t working. If you’re still not falling asleep faster, increase by 0.5 to 1 mg and try another week. Most people find their effective dose somewhere between 1 and 3 mg. If you reach 5 mg with no benefit, the issue is likely not a melatonin deficiency, and taking more won’t fix it.
Melatonin works best for specific situations: adjusting to a new time zone, shifting a delayed sleep schedule, or helping your body recognize “it’s nighttime” when your natural rhythm is off. It’s not a powerful sedative, and it won’t override the effects of caffeine, screen light, or an irregular sleep schedule. If you’re relying on doses above 5 mg nightly for weeks or months, that’s a signal to look at what else might be disrupting your sleep rather than continuing to increase the dose.