A recent preliminary study indicates that long-term use of melatonin supplements may elevate the risk of heart failure and mortality among individuals suffering from chronic insomnia. This research is scheduled for presentation at the American Heart Association’s Scientific Sessions 2025, taking place from November 7-10 in New Orleans.
Melatonin: Natural Hormone with Potential Risks
Melatonin is a hormone produced by the pineal gland that regulates sleep-wake cycles. Its levels rise during the night and fall during the day. Synthetic versions are available over-the-counter in many countries, including the U.S., to treat insomnia and jet lag. However, the regulation of these supplements varies, leading to inconsistencies in strength and purity.
Study Overview
The study analyzed long-term melatonin use by checking electronic health records over a five-year period. Participants were divided into two groups: the “melatonin group,” consisting of individuals who used melatonin for at least 12 months, and the “non-melatonin group,” who had no record of melatonin use. Key findings include:
- Individuals in the melatonin group had a 90% higher chance of developing heart failure compared to non-users (4.6% vs. 2.7%).
- Those with at least two melatonin prescriptions filled at least 90 days apart showed an 82% increased risk.
- Hospitalization rates for heart failure were nearly 3.5 times higher in the melatonin group (19.0% vs. 6.6%).
- Mortality rates were also higher among melatonin users, with a 7.8% death rate compared to 4.3% for non-users.
Expert Insights
Dr. Ekenedilichukwu Nnadi, the study’s lead author, emphasized the alarming association between prolonged melatonin use and serious health outcomes. He noted that the supplements are often perceived as safe, which contrasts sharply with the findings of their study.
Marie-Pierre St-Onge, an expert in sleep health, expressed surprise at the prevalent prescription of melatonin for sleep issues, advocating for awareness regarding its long-term use without appropriate medical guidance.
Implications for Future Research
The study’s findings suggest a critical need for further investigation into the long-term cardiovascular effects of melatonin. Limitations include the study’s reliance on electronic health records, which may not capture all melatonin users, particularly those in countries where it is available over-the-counter.
Study Demographics
The research involved 130,828 adults with an average age of 55.7 years, including 61.4% women. Records were scrutinized to assess the incidence of heart failure and related hospitalizations.
Given the rising use of melatonin supplements, especially among chronic insomnia patients, this study raises essential questions about their safety. Healthcare providers and patients should weigh the potential risks against the benefits when considering melatonin for sleep issues.
