A new study has raised alarms about long-term melatonin use, finding that adults prescribed the popular sleep aid for more than a year face an 89% higher risk of heart failure. The research, which analyzed over 130,000 adults across multiple countries, also showed those taking melatonin long-term were twice as likely to die from any cause compared to non-users.

While melatonin is the fourth most popular natural supplement in the US and widely available over the counter, this analysis suggests its safety profile for extended use needs urgent reassessment. The study's limitations include relying on prescription records rather than direct user surveys, potentially missing those who obtained melatonin without prescriptions. However, a secondary analysis found those taking melatonin for over a year were almost 3.5 times more likely to be hospitalized for heart failure.

Presented at the American Heart Association's Scientific Sessions, these findings challenge the perception of melatonin as a benign sleep solution. Medical experts now call for prospective trials to clarify its safety profile, particularly as usage grows. The research underscores that even natural supplements require careful monitoring, especially for chronic use.