Most adults get the best results from 0.5 to 3 mg of melatonin, taken 30 to 90 minutes before bedtime. That range surprises many people, since store shelves are stacked with 5 mg and 10 mg tablets. But your body naturally produces only about 0.1 to 0.3 mg of melatonin each night, and doses that stay closer to that natural range often work better than mega-doses.
Why Lower Doses Often Work Better
Melatonin is not a sedative. It’s a timing signal: a chemical message that tells your brain darkness has arrived and it’s time to shift into sleep mode. Taking more of it doesn’t produce stronger sleepiness the way a higher dose of a sleeping pill would. In fact, higher doses can overstimulate melatonin receptors and actually disrupt the natural rhythm you’re trying to support.
Research consistently shows that doses above 5 mg rarely improve sleep quality compared to lower amounts, and they increase the likelihood of side effects like morning grogginess, headaches, and vivid dreams. Evidence-based ranges break down roughly like this:
- 0.3 to 1 mg: General sleep timing support, falling asleep a bit earlier
- 1 to 3 mg: Circadian rhythm disorders, persistent trouble with sleep onset
- Up to 5 mg: Occasionally appropriate, but best guided by a healthcare provider
Starting at the lowest effective dose, around 0.5 mg, gives you room to adjust upward if needed. Many people find that 1 mg is enough.
Timing Matters as Much as Dose
Taking melatonin at the right time is just as important as choosing the right amount. For general sleep support, 30 to 90 minutes before your desired bedtime is the standard window. This gives the supplement time to reach meaningful levels in your bloodstream before you want to fall asleep. Taking it too early or too late can shift your internal clock in the wrong direction, making sleep problems worse rather than better.
If you take melatonin and then stay up scrolling your phone under bright lights for another two hours, you’re sending your brain conflicting signals. Dim the lights and wind down around the same time you take it.
Doses for Jet Lag
Jet lag is one of the best-studied uses of melatonin, and the effective dose is lower than most people expect. The CDC notes that 0.5 to 1 mg is often sufficient to produce a meaningful shift in your body clock. Doses above 5 mg are specifically discouraged for jet lag because excess melatonin lingers in your system and can end up active at the wrong time of day as your body processes it, which worsens the misalignment you’re trying to fix.
The timing strategy depends on travel direction. For eastward travel (where you need to fall asleep earlier than your body wants), take melatonin about 90 minutes before your target bedtime to nudge your clock forward. For westward travel (where you need to stay up later), taking it in the morning by your home time zone can help push your clock back. Avoid taking it during the window when your body is already producing its own melatonin, roughly midnight to 5 a.m. on your internal clock, since it won’t add much benefit during that period.
Melatonin for Children
There are no standardized dosing guidelines for children, which makes it especially important to start low. Many children respond well to just 0.5 to 1 mg taken 30 to 90 minutes before bedtime. The American Academy of Pediatrics recommends that parents work with a pediatrician before starting melatonin and that healthy sleep habits (consistent bedtimes, limited screen time before bed, a dark room) should come first.
For children with longer-term sleep difficulties, specialists may prescribe slow-release melatonin starting at 2 mg, with gradual increases up to a maximum of 10 mg depending on the child’s response. But those higher doses are for specific clinical situations, not for general use.
What’s Actually in the Bottle
One complication with melatonin dosing is that what’s printed on the label may not match what’s inside. A study from the University of Guelph that analyzed 31 melatonin supplements found dramatic inconsistencies. The actual melatonin content varied wildly from the labeled amount, and lot-to-lot variability within a single product differed by as much as 465%. Some products contained far more melatonin than advertised. Even more concerning, 26% of the supplements tested contained serotonin, a completely different neurochemical that is much more tightly regulated.
Because melatonin is sold as a dietary supplement in the United States, it doesn’t go through the same manufacturing quality checks that prescription drugs do. Choosing a product from a brand that uses third-party testing (look for USP or NSF certification on the label) can reduce the risk of getting a wildly inaccurate dose.
Side Effects and Interactions
Melatonin has low toxicity overall. Even in extreme cases (a reported overdose of 900 mg), the effects were primarily severe drowsiness rather than organ damage. But that doesn’t mean high doses are harmless in everyday use. Common side effects at typical supplement doses include daytime drowsiness, headaches, dizziness, and nausea, all of which become more likely at higher doses.
Melatonin interacts with several categories of medication. It can increase bleeding risk when combined with blood thinners. It may worsen blood pressure in people taking blood pressure medication. Combined with other sedating substances (alcohol, sleep aids, anti-anxiety medications), it can amplify drowsiness beyond what’s safe. It may also affect blood sugar levels, which matters if you take diabetes medication. People on anti-seizure drugs should be cautious, as melatonin may reduce their effectiveness. Oral contraceptives can intensify melatonin’s sedative effects. And people with autoimmune conditions are generally advised to avoid it entirely, since melatonin stimulates immune activity.
How Long You Can Take It
Melatonin is considered safe for short-term use, generally a few weeks to a few months. The long-term safety picture is less clear simply because there isn’t enough research on nightly use beyond that window. It doesn’t appear to create dependence the way prescription sleep aids can, and your body doesn’t seem to build a tolerance that requires increasing doses over time. Still, if you’ve been relying on melatonin every night for months, that’s worth a conversation with your doctor about whether something else is driving your sleep problems.
For most people, melatonin works best as a short-term tool to reset your sleep timing, not as a permanent nightly fixture. Pairing it with consistent sleep and wake times, a cool and dark bedroom, and reduced light exposure in the evening will do more for your sleep in the long run than any supplement.