Long-Term Use of Melatonin May Increase Heart-Failure Risk
Melatonin, a natural hormone used to regulate the body’s sleep-wake cycle, may not be as harmless as commonly assumed. In a preliminary study of more than 130,000 adults, those who took melatonin for one year or more to treat insomnia were found to have a 90% higher chance of being diagnosed with heart failure within five years. They also were 3.5 times more likely to be hospitalized for heart failure and nearly twice as likely to die from any cause than demographically matched adults who did not take melatonin. The study, presented as an abstract at the American Heart Association Scientific Sessions 2025, was based on a review of electronic medical records, so it cannot prove a direct cause-and-effect relationship. More studies need to be done to confirm the effects of melatonin on the heart. Nevertheless, the findings were concerning, since melatonin supplements are available over the counter and promoted to support better sleep.
