Long-Term Melatonin Use Linked to Higher Heart Failure Risk in Insomnia Patients
A large observational study presented at the American Heart Association’s Scientific Sessions 2025 has found that adults with chronic insomnia who used melatonin supplements for a year or longer were significantly more likely to develop heart failure, be hospitalized for the condition, or die from any cause compared to those who did not take the supplement. The research, which analyzed health data from more than 130,000 adults, raises new questions about the safety of long-term melatonin use, especially among people with persistent sleep problems.
Study Findings
The study, led by researchers from SUNY Downstate/Kings County Primary Care, used data from the TriNetX Global Research Network, a database of de-identified electronic health records. Participants were divided into two groups: those who had taken melatonin for at least one year (the “melatonin group”) and those with no record of melatonin use (the “non-melatonin group”). After adjusting for age, sex, race, and other health factors, the researchers found that long-term melatonin users had about a 90% higher risk of developing heart failure over five years compared to non-users (4.6% vs. 2.7%).
Those who filled at least two melatonin prescriptions at least 90 days apart also showed an 82% higher risk of heart failure. The study further revealed that melatonin users were nearly 3.5 times more likely to be hospitalized for heart failure and almost twice as likely to die from any cause during the study period. These findings were consistent even after accounting for other risk factors, including underlying health conditions and medications.
Expert Commentary
“Melatonin supplements may not be as harmless as commonly assumed,” said Dr. Ekenedilichukwu Nnadi, lead author of the study. “If our findings are confirmed, this could change how doctors counsel patients about sleep aids.”
Experts caution that the study cannot prove that melatonin directly causes heart failure or death. Instead, the association may reflect underlying health issues that drive both chronic insomnia and the need for long-term melatonin use. “Worse insomnia, depression, anxiety, or the use of other sleep-enhancing medicines might be linked to both melatonin use and heart risk,” Nnadi noted.
Dr. Marie-Pierre St-Onge, a professor of nutritional medicine at Columbia University and chair of the American Heart Association’s 2025 scientific statement on sleep health, emphasized that melatonin is not indicated for the long-term treatment of insomnia in the U.S. “Melatonin should not be taken chronically without a proper indication,” she said, highlighting the importance of medical supervision for persistent sleep problems.
Public-Health Implications
Heart failure affects millions of adults worldwide and is a leading cause of hospitalization and death. The study’s findings suggest that people with chronic insomnia who rely on melatonin for extended periods may be at higher risk for serious cardiovascular outcomes. However, because melatonin is widely available over the counter and not regulated in many countries, product quality and dosage can vary, adding to the uncertainty about its safety.
According to the World Health Organization, antimicrobial resistance and other medication safety issues are growing global health concerns, underscoring the need for rigorous research on commonly used supplements like melatonin WHO Global Antibiotic Resistance Surveillance Report 2025.
Next Steps in Research
Researchers stress that more studies are needed to determine whether melatonin itself increases heart failure risk or if the association is due to other factors. Future research should explore the underlying mechanisms and consider the severity of insomnia, psychiatric comorbidities, and the impact of other medications. Until then, patients and healthcare providers should be aware of the potential risks of long-term melatonin use and consider alternative treatments for chronic insomnia.
Read more on Globally Pulse Health for updates on sleep, cardiovascular health, and medication safety.
