Study Questions Melatonin Use and Heart Health, But Don’t Lose Sleep Over It

Don’t lose sleep over headlines linking melatonin to heart failure. That’s the message emerging from some frightening reports of a preliminary study involving the sleep-related supplement. This has raised questions about the safety of long-term use of melatonin for insomnia.

Doctors have long known that insufficient or interrupted sleep increases the risk of heart disease. But cardiology experts say this type of so-called observational study cannot prove that melatonin use plays any role, instead of the insomnia the patients were trying to treat.

“We shouldn’t sound the alarm and tell patients to stop taking all their melatonin,” said Dr. Pratik Sandesara, an interventional cardiologist at Emory Healthcare who was not involved in the research.

Our bodies naturally produce melatonin, a hormone that regulates our sleep cycles. Levels normally increase as night falls, triggering sleepiness.

People can take laboratory-produced melatonin to help them fall asleep or to adjust to jet lag or time changes.

The new study used international electronic health records, tracking adults diagnosed with insomnia who had a melatonin prescription suggesting they used the supplement for at least a year.

Over five years, 4.6% of chronic melatonin users developed heart failure, compared with 2.7% of insomnia patients whose records showed no melatonin use, the researchers found. The study is being presented at an American Heart Association meeting but has not been peer-reviewed.

But only some countries require a melatonin prescription. It is over-the-counter in the United States, meaning Americans in the study may have used the supplements without it being recorded, said Dr. Clyde Yancy, chief of cardiology at Northwestern University, who was not involved in the study. The study also did not show dosages.

Additionally, American supplements do not require government approval, which means brands can vary in their ingredients. Researchers at SUNY Downstate Health Sciences University called the findings a call for more research.

Meanwhile, patients who are wondering about melatonin should discuss it with their doctor, Emory’s Sandesara said. Typically, doctors recommend it for short-term use, such as for jet lag.

Yancy noted that while the study does not prove that there is any harm from long-term use of melatonin, there is also no evidence that people should use melatonin indefinitely.

And to sleep better, it’s essential to practice better sleep hygiene, such as making sure your bedroom is dark.

“When we expose ourselves to blue light, especially at night, we decrease our melatonin levels. It’s science,” he said. Sleep problems aren’t just about “being sleepy and tired: they’re putting you at risk.”

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