Long-term use of melatonin has been linked to a substantially higher risk of heart failure among people with chronic insomnia, according to a large observational study presented at the American Heart Association’s Scientific Sessions.
What the Study Found
Researchers examined five years of health records for 130,828 adults with insomnia, about half of whom had used melatonin for at least a year. Long-term melatonin use was associated with a 90% increased chance of developing heart failure. Melatonin users were also roughly 3.5 times more likely to be hospitalized for heart failure and twice as likely to die from any cause during the five-year follow-up period.
Important Caveats
The findings come from preliminary, observational research and do not prove that melatonin causes heart problems. Chronic insomnia itself, which every participant in the study had, may independently contribute to worse heart health outcomes, and the study cannot rule out that possibility.
What It Means for Melatonin Users
The results raise new questions about the safety of taking the popular over-the-counter sleep supplement for extended periods, even though melatonin is not regulated by the FDA as a drug and is widely available without a prescription in the US.
