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Short-term, nightly melatonin use for up to two months is generally considered safe for most healthy adults. However, experts have concerns about long-term nightly use and about any use for children. For many people, poor sleep stems from lifestyle factors, not low melatonin levels. Supplements are, therefore, often a temporary fix rather than a long-term solution. Here’s what you need to know about what melatonin is, when it might help, why it may not work for you and what you can do instead.
Common side effects include:
If you take melatonin for a long time, your body may become less responsive to it as it builds tolerance, making it less effective.
According to the American Heart Association, preliminary 2025 research suggests that people who use melatonin for 12 months or more may have a 90% higher risk of heart failure over five years.
While this sounds alarming, it is important to note that the study had several limitations and that, while it found a significant correlation, it did not demonstrate cause and effect — other explanations could have accounted for the observed effect.
Nevertheless, while research continues, you may wish to use melatonin only for short-term use.
No, melatonin is not a sleeping pill or a sedative. This is a common misconception. Melatonin is a hormone produced by your pineal gland when it gets dark. It signals to your body that it’s time to sleep, but it doesn’t “make” you sleep. It simply regulates the natural sleep-wake cycle as part of your circadian rhythm — the body’s internal clock. When you take a melatonin supplement, it induces the sense of quiet calm that promotes sleep.
“Most people’s bodies produce enough melatonin for sleep on their own,” explains Luis F. Buenaver, PhD, C.B.S.M, a sleep expert with Johns Hopkins Medicine. However, there are times when you might benefit from taking a supplement, such as:
In these situations, your body is producing enough melatonin by itself, but crucially not at the time when you most need it. A circadian rhythm mismatch can be helped by supplementation until your natural cycle catches up.
Older adults who are not sleeping well can also benefit from supplements, because melatonin production declines with age, so they may not be producing as much as they need.
If your sleep pattern is disrupted by lifestyle factors rather than underlying physiology, melatonin supplements may only work for a short time, or not at all.
Before reaching for these pills, consider whether any of the following might be the cause of your sleeping problem.
| Factor | Why It Interferes With Sleep |
| Blue Light/Screens Before Bed | Exposure to blue light tricks the brain into thinking it’s still daytime. This suppresses the production of melatonin. |
| Inconsistent Sleep Schedule | Going to bed and waking up at inconsistent times confuses your internal clock. |
| Caffeine Too Close to Bedtime | Caffeine is a stimulant that blocks adenosine, a chemical that promotes sleepiness. |
| Lack of Physical Exercise | Exercise produces adenosine that makes you feel tired. If you have too little in your body at night, you may not sleep well. |
| Chronic Stress | Stress triggers the release of cortisol and adrenaline, which are part of the body’s fight-or-flight response. This makes it difficult for you to fall asleep. |
If these are your core problems, address them first by reducing evening screen time. “Melatonin levels rise about two hours before bedtime,” explains Buenaver. “Create optimal conditions for it to do its job by keeping the lights low before bed. Stop using your computer, smartphone or tablet — the blue and green light from these things can neutralize melatonin’s effects.”
You could also try setting a consistent bedtime, adjusting it by 15 minutes a day until you find what’s right for you. It’s also important to avoid caffeine at night, get plenty of exercise and take measures to reduce your stress. These solutions are more likely to help long-term than melatonin supplements.
The World Journal of Pediatrics recommends that melatonin should not be given to children without medical supervision.
This is due to a lack of long-term safety data. Researchers have also found that over-the-counter melatonin supplements:
These are serious concerns in a country like the U.S., where melatonin does not require a prescription. If you are concerned about your child’s sleep, and better bedtime routines don’t help, consult a health professional before giving them melatonin.
Start with the lowest possible dose. Buenaver suggests “Take 1 to 3 milligrams two hours before bedtime. Less is more.”
If supplements are going to help you, you should notice a difference within a week or two. If, after that, your sleep pattern has not improved, Buenaver advises that you should stop taking the pills. If you have also tried lifestyle adjustments and are still struggling, talk to your health care provider.
No, melatonin is not physically addictive, unlike some sleep medications. However, it is possible to form a psychological/habitual dependence on it, where a person may feel they cannot sleep without it. If this happens to you, talk to a doctor about tapering use gradually.
It is not harmful to take melatonin every night for up to 2 months to help with jet lag, shift work or temporary insomnia. However, early research has raised some potentially serious concerns about ongoing long-term use or use for children. Melatonin does not help everyone, so try addressing screen time, caffeine, stress and a lack of exercise first. Healthy sleep is important, so don’t hesitate to contact your doctor if you have concerns about your sleep regimen or melatonin use.
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