According to a new study presented at the American Heart Association’s Scientific Sessions 2025, the long-term use of melatonin (to treat insomnia) may be associated with an increased risk of heart failure. This finding is significant because melatonin is widely considered a safe and natural sleep aid.
The study analyzed the medical data of nearly 131,000 adults diagnosed with insomnia.
It was found that people who took melatonin for more than 12 months had a 90% increased risk of heart failure over a 5-year period compared to those who did not use the medication at all. Furthermore, melatonin users had an approximately 3.5-fold higher risk of hospitalization due to heart failure, and the risk of death from any cause was twice as high.
Although the study indicates a connection between long-term melatonin use and serious health problems, these results are unexpected, as some previous studies considered melatonin potentially beneficial for the cardiovascular system.
However, experts note that it is essential to evaluate this correlation considering that the cohort of patients using melatonin for sleep problems may already have an increased risk of cardiovascular diseases. Accordingly, in many cases, melatonin is taken precisely because existing cardiovascular issues prevent them from falling asleep. In other words, insomnia itself can be an early sign of heart failure or sleep apnea.
Experts note that the production of melatonin is not adequately regulated by the FDA, which leads to variability in dosage and composition. Furthermore, it is possible that insomnia itself may be an early sign of heart failure or sleep apnea.
Scientists are calling for more rigorous studies to confirm these results and clarify exactly how melatonin affects the heart.
