Long-term Melatonin Use Linked to Higher Risk of Heart Failure and Death

A new study analyzing 5 years of health records for over 130,000 adults with insomnia found that those who used melatonin supplements for more than a year had a significantly higher risk of heart failure, hospitalization for heart failure, and death from any cause. The association between melatonin use and increased risk of heart failure or death raises safety concerns and warrants further research on the cardiovascular safety of melatonin supplements, which are widely available over-the-counter.

Key Takeaways:

• Adults with insomnia who used melatonin supplements for more than a year had a 90% higher chance of incident heart failure over 5 years compared to non-users.
• Those taking melatonin were nearly 3.5 times as likely to be hospitalized for heart failure and nearly twice as likely to die from any cause than those not taking melatonin.
• The study found a consistent and significant increase in serious health outcomes, even after balancing for many other risk factors.
• The researchers cautioned that the association found in the study does not prove a direct cause-and-effect relationship and that more research is needed to test melatonin's safety for the heart.
• Melatonin use was associated with a higher risk of heart failure and death despite controlling for factors such as age, sex, race/ethnicity, and medications.
• The study's findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

Statistics:

• 65,414 participants had been prescribed melatonin at least once and reported taking it for at least a year.
• 130,828 adults (average age of 55.7 years; 61.4% women) diagnosed with insomnia were included in the study.
• 4.6% of adults with insomnia who used melatonin for more than a year developed incident heart failure over 5 years compared to 2.7% of non-users.
• 19.0% of participants taking melatonin were hospitalized for heart failure compared to 6.6% of those not taking melatonin.
• 7.8% of participants in the melatonin group died from any cause over 5 years compared to 4.3% of the non-melatonin group.

Sources:

• Research Highlights: A review of 5 years of health records for more than 130,000 adults with insomnia who had used melatonin for at least a year found they were more likely to be diagnosed with heart failure, require hospitalization for the condition or die from any cause.
• American Heart Association (2025). Abstracts presented at the American Heart Association's scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as full manuscripts in a peer-reviewed scientific journal.
• Ekenedilichukwu Nnadi, M.D., chief resident in internal medicine at SUNY Downstate/Kings County Primary Care in Brooklyn, New York.
• Marie-Pierre St-Onge, Ph.D., C.C.S.H., FAHA, chair of the writing group for the American Heart Association's 2025 scientific statement.