Most people take melatonin nightly, but starting with two or three nights per week is often enough to improve sleep. The NHS notes that some doctors recommend this lower frequency first to see if it helps before committing to every night. How often you take it also depends on why you’re using it: a few days for jet lag, a short stretch for temporary insomnia, or a longer run for chronic sleep problems.
Nightly vs. a Few Times Per Week
There’s no single rule for how many nights per week you should take melatonin. For general insomnia, nightly use is the most studied approach, with clinical trials typically giving participants a dose every night for three to five weeks. But if your sleep trouble is mild or inconsistent, taking it only on the nights you struggle can work just as well. The key is using it as a tool for specific nights rather than an automatic part of your routine if you don’t need it every night.
For jet lag, the pattern is much simpler: take it once a day for up to five days, starting the night you arrive in your new time zone. The CDC recommends taking it about 90 minutes before your target bedtime for eastward travel. You stop once your body adjusts. There’s no reason to continue beyond that window.
Timing and Dose
Take melatonin one to two hours before you want to fall asleep. This lines up with when your brain naturally begins releasing its own melatonin in the evening. If you miss your window, skip that night and try again the next day rather than taking it late.
The dose most people need is far lower than what’s sold in stores. Research from MIT found that 0.3 milligrams is enough to mimic the body’s natural melatonin levels and restore sleep in adults over 50. Most supplements start at 1 mg, and many contain 5 or even 10 mg. The generally recommended maximum is 5 mg or less. Higher doses can actually backfire: the CDC warns that anything above 5 mg can leave excess melatonin circulating at the wrong time of day, which disrupts your sleep cycle rather than supporting it.
For jet lag specifically, 0.5 to 1 mg is often sufficient to shift your body clock.
How Long You Can Take It
Melatonin is considered safe for short-term use, generally a few weeks to a couple of months. Most clinical trials have studied periods of three to five weeks. Beyond that, the safety picture gets murkier.
A large study presented at the American Heart Association’s 2025 meeting raised concerns about long-term use. Researchers tracked over 65,000 people who had been prescribed melatonin for at least one year and compared them to a similar group not taking it. Over five years, the melatonin group had a higher rate of heart failure (5% vs. 3%), significantly more heart failure hospitalizations (19% vs. 7%), and roughly double the rate of death from any cause (8% vs. 4%). These results held up even after the researchers accounted for other health differences between the groups. This doesn’t prove melatonin caused these outcomes, since people with worse sleep may already have higher health risks, but it’s a reason to be cautious about taking it indefinitely without a plan to stop.
Tolerance and Dependency
Melatonin does not cause addiction or physical dependence. There’s no evidence that your body builds a tolerance to it, meaning you shouldn’t need to increase your dose over time for the same effect. You also won’t experience withdrawal symptoms if you stop taking it abruptly. No tapering is necessary.
That said, your sleep problems will typically return to whatever they were before you started. Melatonin doesn’t fix the underlying cause of insomnia. It shifts the timing of your sleep signals, which is why it works well for circadian rhythm issues like jet lag or delayed sleep phase but may do little for someone whose insomnia is driven by anxiety, pain, or poor sleep habits.
Children and Melatonin
There are no official dosing guidelines for how often children should take melatonin. The American Academy of Pediatrics considers it a short-term option while families work on building better sleep routines, not a long-term nightly solution. Short-term use appears relatively safe in children, but less is known about what happens with months or years of regular use, which is particularly relevant since melatonin interacts with hormonal systems that are still developing. If your child is using melatonin frequently, it’s worth revisiting whether the underlying sleep issue can be addressed through behavioral changes like consistent bedtimes, reduced screen time before bed, and a dark, cool sleeping environment.
Older Adults
Adults over 55 produce less melatonin naturally, which is one reason sleep quality tends to decline with age. Clinical trials in this age group have consistently used 2 mg of a slow-release formulation taken nightly, with study periods lasting three to five weeks. The slow-release form matters here because it keeps melatonin levels steady through the night, more closely mimicking natural production, rather than spiking and dropping quickly.
Older adults also metabolize melatonin more slowly, so lower doses tend to be more appropriate. Starting at the lowest available dose and only increasing if needed keeps side effects like morning grogginess to a minimum.
A Practical Approach
If you’re trying melatonin for the first time, start with two or three nights per week at a low dose (0.5 to 1 mg), taken one to two hours before bed. If that helps, you can use it more frequently. If it doesn’t, increasing the frequency to nightly is a reasonable next step before increasing the dose. Keep use to a few weeks at a time when possible, and if you find yourself relying on it for months, that’s a signal to look more closely at what’s actually disrupting your sleep.