If you’re one of the many people chowing down on melatonin gummies to help get to sleep, you may want to check out this study.

A new piece of research published by the American Heart Association made an alarming discovery about long-term use of melatonin supplements, an over-the-counter sleep aid used by tens of thousands. Basically, those who use melatonin over a year or more had a 90 percent higher risk of developing congestive heart failure over a five-year period.

Before you go flush your gummies down the toilet, there are a few caveats. For starters, the findings weren’t based on a clinical trial, but on data from a large database of anonymous health records. Researchers drew from data on chronic insomniacs, specifically, splitting them into two groups: those who have dosed the sleep-regulating hormone over a period of 12 months or more, and those who suffer without.

Still, the results are clearly worrisome. Overall, the study found that 4.6 percent of the melatonin group went on to develop heart failure, compared to 2.7 percent for the control group.

That wasn’t the only data point suggesting it may be time to ween off the ‘tone. A secondary analysis performed by the researchers found that melatonin users were nearly 3.5 times more likely to be hospitalized for heart failure than those in the other group, with hospitalization rates of 19.0 and 6.6 percent, respectively.

“Melatonin supplements are widely thought of as a safe and ‘natural’ option to support better sleep, so it was striking to see such consistent and significant increases in serious health outcomes, even after balancing for many other risk factors,” Ekenedilichukwu Nnadi, the study’s lead author and chief resident in internal medicine at SUNY Brooklyn, said in a press release.

While more in-depth research is needed to confirm the study’s results, the early findings indicate that melatonin use comes with some serious risks in the long-term.

“Melatonin supplements may not be as harmless as commonly assumed,” as Nnadi explained. “If our study is confirmed, this could affect how doctors counsel patients about sleep aids.”

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