A preliminary study to be presented at the American Heart Association’s Scientific Sessions 2025 revealed a shocking update regarding the long-term use of melatonin.
The research suggested long-term use of melatonin supplements may be tied to a significantly higher risk of adverse cardiac events that may require urgent medical attention and may become fatal in individuals suffering from chronic insomnia.
For the study, researchers assessed five years of electronic health records from over 130,000 adults with insomnia using the TriNetX Global Research Network.
People who used used melatonin for a year had a 90% increased risk of developing heart failure in contrast to the matched non-users (4.6% vs. 2.7%), were 3.5 times more likely to get hospitalised for cardiac failure (19.0% vs. 6.6%), and at an increased risk of death from any cause (7.8% vs. 4.3%).
Lead author Dr. Ekenedilichukwu Nnadi of SUNY Downstate stated the research challenges the assumption that melatonin has no adverse effect.
Experts mentioned that melatonin remains unapproved in the U.S. for long-term insomnia treatment and that supplement strength and purity may differ due to its unregulation.
Researchers emphasized that while the associations raise safety concerns, causation was not proven and further research is needed to confirm melatonin’s long-term cardiovascular safety.
It is pertinent to mention the study has limitations, including potential misclassification since over-the-counter melatonin users across the US may have been counted as non-users, and hidden factors, including insomnia severity or psychiatric conditions.
Researchers further underscored that while the link raise concerns regarding safety; however, causation remains unproven, and researchers further stressed the need to confirm melatonin’s long-term cardiovascular safety.
