More Americans Using Melatonin Supplement For Sleep Despite Unknown Long-Term Safety: Study

More American adults are using melatonin to help them sleep, and some in greater doses than recommended, a new study has found. So far, the long-term safety of the supplement is not known.

Melatonin has been regarded as "generally safe," researchers of a new study, published Tuesday in the journal JAMA, said. However, there have been reports of its adverse effects. In addition, its long-term safety remains unknown, CNN noted.

For their study, the researchers had a look at the trends in melatonin use among 55,021 adults from 1999 to 2018 using data from the National Health and Nutrition Examination Survey. They found that the prevalence of melatonin use "significantly increased" during this period "across all demographic groups." The prevalence of melatonin use was only at 0.4% during the 1999-2000 cycle of the survey, but it climbed to 2.1% by 2017-2018, with the increase being observed starting 2009-2010.

The researchers also found an increase in the use of more than 5 milligrams of melatonin even though the recommended dosage typically does not exceed that amount. This increase was observed starting 2005-2006, when the prevalence rate was 0.08%. This increased to 0.28% by 2017-2018.

"These estimates may raise safety concerns, especially given that the actual content of melatonin in marketed supplements may be up to 478% higher than the labeled content and that evidence supporting melatonin use for sleep disturbances is weak," the researchers wrote.

This shows the importance of having a better understanding of the long-term safety of using melatonin, the researchers added. As mentioned, this has so far been unclear.

"There is a view that if it's natural, then it can't hurt," Rebecca Robbins, an instructor in the sleep medicine division at Harvard Medical School who was not involved in the study, previously told CNN. "The truth is, we just really don't know the implications of melatonin in the longer term, for adults or kids."

By 2012, it was estimated that about 3 million Americans were using melatonin sleep aids. According to Johns Hopkins Medicine, anyone who's considering using them should better understand how melatonin works.

As Johns Hopkins sleep expert Luis F. Buenaver, Ph.D., C.B.S.M. explained, melatonin is a hormone that the body produces naturally.

"It doesn't make you sleep, but as melatonin levels rise in the evening it puts you into a state of quiet wakefulness that helps promote sleep," Buenaver said.

When taking melatonin supplements "on a short-term basis" under certain conditions, such as when experiencing occasional insomnia or trying to overcome jetlag, Buenaver noted that "less is more."

Before considering taking melatonin, the Mayo Clinic recommends that people should see a doctor first, especially those who have health conditions since melatonin can interact with certain medications.