For most adults, 1 to 5 mg of melatonin taken one to two hours before bedtime is the typical range for sleep support. The NHS sets a maximum prescribed dose of 10 mg daily for longer-term insomnia, though most people find lower doses effective. Starting at the lowest dose that works for you is the smartest approach, because more melatonin doesn’t necessarily mean better sleep.
Standard Doses for Adults
The usual starting point for short-term sleep trouble is 2 mg of a slow-release tablet, taken one to two hours before bed. For persistent insomnia, that dose can gradually increase to a maximum of 10 mg per night if lower amounts aren’t helping. For jet lag, 3 mg taken at bedtime (no earlier than 8 p.m. and no later than 4 a.m.) for up to five days is standard, with 6 mg as the upper end.
Here’s the key point many people miss: your body naturally produces melatonin in very small amounts. Supplemental doses of 1 to 3 mg already push blood levels well above what your brain produces on its own. Taking 10 or 20 mg doesn’t make you fall asleep twice as fast. In many cases, lower doses (even 0.5 mg) work just as well as higher ones for shifting your sleep timing.
Why “More” Often Backfires
Melatonin isn’t a sedative. It’s a signal. Your pineal gland releases it when the sun goes down, telling your brain’s internal thermostat to lower your body temperature, reduce blood pressure, and dial back alertness. Your eyes even become less responsive to light. A supplement mimics that signal, nudging your body toward sleep readiness.
When you flood your system with a large dose, you can end up with too much melatonin circulating in your blood, a condition sometimes called hypermelatoninemia. Instead of sleeping better, you may wake up groggy, drowsy, or with a headache the next morning. Some people experience dizziness or nausea. The goal is to find the smallest dose that helps you fall asleep, not the largest dose you can tolerate.
Doses for Children
There are no official dosage guidelines for children, which makes this trickier. Most children who benefit from melatonin respond to 3 to 6 mg, and pediatric sleep experts recommend starting at the lowest possible dose. Between 2012 and 2021, poison control centers received more than 260,000 reports involving children and melatonin, many from kids accessing bottles that look like candy gummies.
Long-term safety data for children is limited. A systematic review in The Lancet’s eClinicalMedicine found that melatonin wasn’t associated with serious adverse events in children, but non-serious side effects (morning sleepiness, headaches, increased bedwetting) were more common compared to placebo. Three studies tracking children for two to four years found little effect on puberty, but one study following kids for more than seven years flagged a potential delay in pubertal development. The evidence is too thin to draw firm conclusions, which is why most pediatricians treat melatonin as a short-term tool rather than a nightly habit.
Doses for Older Adults
Adults over 55 are the group with the most clinical trial data. Multiple randomized trials have tested 2 mg of prolonged-release melatonin nightly in people ranging from their mid-50s to early 90s. Side effects at that dose were minimal, occurring at rates nearly identical to placebo. The American Academy of Sleep Medicine’s guidelines actually give only a weak endorsement for 2 mg melatonin in older adults, noting that the sleep benefits were small in the available trials. That doesn’t mean it won’t help you individually, but it does mean expectations should be modest.
The Label Accuracy Problem
One of the biggest issues with melatonin has nothing to do with dosing guidelines. In the United States, melatonin is sold as a dietary supplement, not a regulated medication. The FDA does not approve it for sleep, and manufacturers don’t have to prove their labels are accurate before selling.
A study highlighted by the American Academy of Sleep Medicine found that more than 71% of melatonin supplements failed to contain within 10% of what their label claimed. Actual melatonin content ranged from 83% less to 478% more than what the bottle said. Even different batches of the same product varied by as much as 465%. On top of that, 26% of the tested supplements contained serotonin, a completely different brain chemical that wasn’t listed on the label. So when you take a “5 mg” gummy, you might be getting anywhere from less than 1 mg to nearly 25 mg of actual melatonin.
If accuracy matters to you, look for products that carry a third-party testing seal from organizations like USP or NSF International. These verify that what’s on the label matches what’s in the bottle.
Signs You’ve Taken Too Much
Melatonin has a wide safety margin, and no lethal dose has been established in humans. But “not deadly” doesn’t mean “no consequences.” Taking more than your body needs commonly causes:
- Next-day drowsiness that lingers well into the morning
- Headaches
- Dizziness
- Nausea
- Vivid dreams or nightmares
If you’re waking up feeling more tired than before you started taking melatonin, your dose is likely too high. Try cutting it in half. Many people do better dropping from 5 mg down to 1 or 2 mg.
Timing Matters as Much as Dose
Taking melatonin at the right time is at least as important as getting the dose right. For general sleep trouble, take it one to two hours before you want to fall asleep. Taking it too early in the evening or too late at night can shift your sleep cycle in the wrong direction.
For jet lag, the timing rule is simple: take it at bedtime in your new time zone, but only between 8 p.m. and 4 a.m. Taking it outside that window can worsen jet lag by confusing your internal clock further. Limit jet lag use to five days or fewer.
Melatonin also works best in a dim environment. Bright overhead lights and phone screens suppress your natural melatonin production, which can undercut the supplement you just swallowed. Dimming lights 30 to 60 minutes before bed lets the supplement work with your biology instead of against it.