Lindsey Bever
Many people struggle to get a good night’s sleep at some point or another. Anxiety, stress and even your natural tendency to be a night owl or morning lark can interfere with the seven to nine hours of sleep that’s often recommended for folks to get each night.
That can be a problem because sleep is essential to your health. Research shows that poor sleep is associated with increased risks of obesity, Type 2 diabetes, hypertension, cardiovascular disease and more.
If you’re having trouble sleeping, studies show that some over-the-counter supplements such as melatonin and magnesium may help. But there are caveats: neither act as a sedative or can treat sleep disorders such as chronic insomnia – when you have difficulty falling or staying asleep at least three times a week for three months or more.
Keep in mind that you should always talk to your doctor before starting any supplement. Melatonin, for example, is only available in Australia over the counter in low-dose form for those aged 55 and over for short-term insomnia, or adults over 18 as a treatment for jet lag.
So how do you know whether to consider melatonin or magnesium? We spoke to health experts and combed through the research to help answer that question.
Melatonin: If you have trouble falling asleep
Melatonin supplements can help align your body’s internal clock with the sun to help you achieve your desired sleep schedule, says Anita Shelgikar, immediate past president of the American Academy of Sleep Medicine and a professor of neurology at the University of Michigan Medical School.
The supplement can be helpful for people who are naturally inclined to stay up very late or wake up very early, making it difficult to follow a typical work, school or social schedule. People who work night shifts or are experiencing jet lag may also benefit.
The supplement works by mimicking the hormone produced by the pineal gland in the brain that regulates your sleep-wake cycle. Your brain responds to darkness by releasing melatonin to promote sleepiness. Melatonin levels then wane toward the morning, helping you wake up.
A 2024 review of 26 randomised controlled trials found that melatonin reduced the time it took to fall asleep and increased the total time people slept, with the most notable results at 4 milligrams of melatonin per day, taken three hours before the desired bedtime.
Taking low doses – about 1-3 mg daily for a few weeks – is generally considered safe for most healthy adults. But you shouldn’t exceed 5 mg in most cases as there is no reliable evidence that larger doses provide better results, says Michael Grandner, director of the Sleep and Health Research Program at the University of Arizona.
It’s also better to err on the lower end of dosing because supplements tend to be more potent than the listed dosage when fresh from the manufacturer, then degrade to the listed dosing over time, Grandner says. And he prefers a quick-dissolve formulation, when possible. With gummies, it’s hard to know exactly how much melatonin you’re getting or when it will be absorbed, he says.
Generally, you should take melatonin two to three hours before your desired bedtime. Shelgikar also recommends keeping a consistent bedtime and wake time, and exposing yourself to bright light upon waking and dimmer light about an hour before bedtime.
But if that doesn’t seem to be working, consult a medical professional for a tailored treatment plan, because taking a melatonin supplement at the same time that your brain is producing its own melatonin will not provide any added benefit because your “melatonin receptors are full,” she says.
Children should not be given more than 1 mg daily and should take melatonin only under the supervision of a pediatrician. Accidental overdoses in kids have led to hospitalisations, says Pieter Cohen, an internist at Cambridge Health Alliance and associate professor at Harvard Medical School.
The American Academy of Sleep Medicine recommends against using melatonin for chronic insomnia in adults.
The odds that any nutritional supplement will help treat insomnia “are very low,” Grandner says.
Melatonin: If you’re older or take beta blockers
As you age, your body’s nighttime production of melatonin gradually declines. Also, certain medications that are more common with age – particularly beta blockers – can further suppress the body’s natural nighttime melatonin production, Grandner says.
In such cases, a low-dose melatonin supplement – he generally recommends less than 5 mg – may help replace some of the melatonin the body is no longer producing, he says.
But it’s important to note that melatonin can also interact with certain medications, including blood thinners, and it may lessen the effects of anti-seizure medications and immunosuppressants.
Magnesium: If you have muscle tension or mild sleep issues
Magnesium supplements aren’t backed by as much research as melatonin for sleep issues. And in general, it’s best to get magnesium from your diet – in foods such as green leafy vegetables, legumes, nuts, seeds and whole grains – rather than a supplement.
But asked whether he ever recommends magnesium supplements to patients, Grandner says he has “no hesitation in recommending it for people who have more mild or transient issues, or if they want to boost what they’re already doing. It’s likely not harmful, and it’s likely at least a little bit helpful, but just don’t expect more from it than it can deliver.”
There are two theories as to why magnesium may support better sleep. First, magnesium plays a role in the body’s production of melatonin. To produce melatonin, the body converts an amino acid called tryptophan into serotonin, and magnesium helps support an enzyme involved in converting serotonin into melatonin, Grandner says.
Secondly, magnesium helps maintain normal nerve and muscle function, and may help promote muscle relaxation, although evidence that it relieves muscle cramps is mixed.
Trials on how magnesium supplementation impacts sleep have been small or shown minor benefits. One small trial published in 2025 found that people who took 250 mg of magnesium bisglycinate every day for a month had improved sleep over the placebo group.
“The effects generally are not as large as people tend to think they are, but they’re not nothing either,” says Grandner, who was not involved in the study.
If you want to try magnesium, Shelgikar suggested taking 250 mg of magnesium glycinate daily as part of your bedtime routine. But she said that recommendation is largely based on anecdotal evidence, since the data on magnesium for sleep is limited, and you should check with a doctor if you continue to have sleep issues after a few weeks.
Also, you should avoid taking magnesium citrate if your goal is to improve sleep, because it’s more commonly used as a laxative, “and that’s certainly not something you want to take at night,” Cohen says.
Keep in mind the potential gastrointestinal side effects from magnesium – diarrhoea, vomiting and abdominal cramping. Magnesium can also interact with some prescription medications such as some antibiotics, blood pressure medications and bone-loss drugs, and may worsen certain medical conditions including a neuromuscular disorder called myasthenia gravis, Shelgikar says.
Washington Post
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