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Is melatonin safe as a sleeping aid?

Inaccurate labelling of over-the-counter products makes accidental overdoses more likely — and kids, due to their size, are at greater risk.
Image by JOE RAEDLE / Getty Images.

This article was originally posted in the Montreal Gazette.

Many people complain of insomnia and want something to help them sleep. Melatonin is a common choice. It’s seen as a safe, effective, all-natural treatment available without a prescription. It’s often given to children to help with sleep, stress and relaxation. But a new report in the Journal of the American Medical Association suggests that health halo may not be deserved. Many commercially available melatonin gummies have more, and sometimes much more, melatonin than their label suggests.

While the biochemistry is a bit more complicated than is often laid out, your body uses melatonin to set your circadian rhythm. Daylight suppresses melatonin production, while the onset of darkness means that melatonin levels rise and heralds the onset of sleep. The suggestion to avoid phones and tablets before bed serves to limit artificial light that would suppress melatonin production and disrupt sleep. In theory, taking melatonin tablets should have a similar result and facilitate sleep onset.

The research on the subject is more muted as to its benefit. Melatonin seems to primarily affect sleep onset or your ability to fall asleep, not necessarily sleep quality or your ability to stay asleep. This would make it more useful for issues like jet lag. But even so, the magnitude of the benefit is modest, with total sleep time being increased by on average 13 minutes.

Whether this benefit is significant enough to justify its use is a question for another day. Nevertheless, many people try melatonin because of the perception that it is harmless and risk free. But its popularity as a sleep aid does carry risks. Between 2012 and 2021 the Centers for Disease Control and Prevention in the United States noted the number of pediatric melatonin overdoses reported to poison control centres increased five-fold. Most children recovered and only around 15 per cent of those seeking medical care required hospitalization. Still the number of accidental ingestions and serious complications has increased over the past decade, and we ignore that issue at our own peril.

The CDC report could not ascertain the reason for the increase in accidental exposures, but the growing popularity of melatonin as a sleep aid surely played a role. The largest increase in accidental exposures occurred at the onset of the COVID-19 pandemic when more people presumably turned to this over-the-counter product to help them fall asleep. Side-effects can include drowsiness and dizziness but also headaches, stomach cramps, irritability and vivid dreams or nightmares.

The new report in JAMA highlights another issue. Because melatonin is regulated as an over-the-counter dietary supplement, rather than as medication, there seems to be greater variability in dosing and labelling. The report analyzed 25 melatonin gummy brands and compared the dose relative to the label. One product had no melatonin in it. Most had more. Only three had accurate labels, meaning the amount of measured melatonin was within 10 per cent of the dose indicated on the label.

For context, around one milligram of melatonin is likely sufficient to get the sleep benefit. One of the products in this study had a label listing three milligrams as the dose, which is somewhat on the higher side. It actually contained over 10 milligrams. A 2017 report found similar problems with melatonin supplements where what is in the bottle didn’t match up with what was on the label.

Inaccurate labelling makes accidental overdoses more likely — and children, due to their smaller size, are at greater risk. It is tempting to think over the counter products are safe, and they generally are. But, paradoxically, because melatonin is regulated as a dietary supplement in the U.S. and as a natural health product in Canada, rather than as prescription medication, there appears to be more variability in the doses that are commercially available.

Some people argue that supplements and other products don’t need the same oversight we have for prescription medication. I disagree. If you use something for medical purposes, it should be subject to the same regulations. It should work, it should be safe, and what’s on the label should be true.


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