A significant study presented at the American Heart Association’s Scientific Sessions 2025 has raised concerns about the long-term use of melatonin supplements in adults suffering from insomnia. Researchers reviewed five years of health records for over 130,000 adults and found a troubling association between long-term melatonin use and increased risks of heart failure, hospitalization, and mortality from any cause.
The study classified participants into two groups: those with documented long-term use of melatonin (defined as at least a year of use) and those who had no record of melatonin in their medical history. The findings indicated that chronic insomnia patients using melatonin were approximately 90% more likely to develop heart failure compared to non-users (4.6% versus 2.7%). Furthermore, the data revealed that individuals in the melatonin group were nearly 3.5 times more likely to be hospitalized due to heart failure and almost twice as likely to die from any cause during the study period.
Lead author Dr. Ekenedilichukwu Nnadi emphasized the need for a reevaluation of how sleep aids, particularly melatonin, are prescribed. With melatonin regarded as a safe option for sleep by many, these findings highlight that its potential cardiovascular implications merit further investigation. Dr. Marie-Pierre St-Onge, chair of the American Heart Association’s writing group, added that it is concerning that melatonin is often prescribed for periods exceeding 365 days without proper medical indications.
Despite melatonin’s natural production in the body and its common use as an over-the-counter supplement, this study highlights a lack of long-term safety data regarding its impact on cardiovascular health. The researchers controlled for various factors, such as age, sex, and underlying health conditions, but acknowledged that the study had limitations, including the diversity of regulations regarding melatonin prescriptions across countries.
Given the preliminary nature of this study, further research is essential to establish a clearer understanding of melatonin’s risks and potential impacts on heart health. While melatonin may still be used by many as a tool for managing sleep issues, these findings suggest that greater scrutiny is warranted in its long-term use, particularly for those suffering from chronic insomnia.
This research underscores the importance of patient education and awareness regarding supplements and medications. As ongoing studies address these concerns, the hope remains that safe and effective strategies for improving sleep can be identified.