Dallas, November 3, 2025 – A preliminary study to be presented at the 2025 American Heart Association Scientific Sessions suggests that long-term use of melatonin supplements (commonly used to improve sleep and treat insomnia) is associated with an increased risk of heart failure, heart failure-related hospitalizations, and all-cause mortality in patients with chronic insomnia. The Scientific Sessions, taking place in New Orleans from November 7 to 10, will provide a leading global platform for sharing the latest scientific advances, research findings, and evidence-based clinical practices in cardiovascular science.
Melatonin is a hormone naturally produced by the human pineal gland and involved in regulating the sleep-wake cycle. Melatonin levels rise in darkness and decline during the day. Synthetic melatonin, which has the same chemical structure, is often used to treat insomnia (difficulty falling and/or staying asleep) and jet lag. In many countries, including the United States, these supplements are available over-the-counter. In the United States, over-the-counter supplements do not require government approval to ensure quality and consistency; therefore, different brands of supplements may vary in potency, purity, etc. (Previous sentence updated November 5, 2025)
In this study, researchers classified those who had taken melatonin long-term (for a year or more, as documented in their electronic medical records) as the “melatonin group.” Those whose medical records did not record melatonin use were classified as the “non-melatonin group.”
”Melatonin supplements may not be as safe as commonly believed. If our study confirms this, it could impact how doctors recommend sleep medications to patients,” said Dr. Eknedi Lichuku Nadi, chief internal medicine resident at SUNY Downstate/Kings County Primary Care and lead author of the study.
Melatonin supplements are marketed and advertised as a safe sleep aid. However, the lack of data on their long-term cardiovascular safety has prompted researchers to examine whether melatonin supplementation affects the risk of heart failure, particularly in patients with chronic insomnia. According to the American Heart Association’s 2025 Heart and Stroke Statistics, heart failure is a common condition affecting 6.7 million adults in the United States. It occurs when the heart is unable to pump enough oxygenated blood to the organs to maintain normal function.
Researchers used a large international database (TriNetX Global Research Network) to analyze the electronic medical records of adults who had suffered from chronic insomnia for the past five years and had taken melatonin for more than a year. They compared these individuals with peers in the database who also suffered from insomnia but whose medical records did not record melatonin use. Patients with previously diagnosed heart failure or taking other sleep medications were excluded from the analysis.
”Melatonin supplements are widely considered a safe and ‘natural’ way to help improve sleep, so it’s alarming to see such a sustained and significant increase in serious health problems, even after addressing many other risk factors,” Nadi said.
”I’m surprised that a physician would prescribe melatonin to a patient with insomnia and that the patient would take it for more than 365 days, because melatonin is not approved for the treatment of insomnia, at least in the United States. Melatonin is available as an over-the-counter supplement in the United States, and people should be aware that it should not be taken long-term without a proper indication,” said Marie-Pierre St-Onge, MD, a registered sleep health clinician and fellow of the American Heart Association, and chair of the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health.” St-Onge was not involved in the study; she is a professor of internal medicine and nutrition at Columbia University Irving Medical Center in New York City and director of the center’s Center of Excellence for Sleep and Circadian Rhythms.
This study has several limitations. First, the database includes countries where melatonin requires a prescription (e.g., the UK) and countries where it is not (e.g., the US), and the de-identified data available to the researchers did not include patient location information. Because melatonin use in the study was based solely on medication records in electronic health records, all patients taking over-the-counter melatonin supplements in the US or other countries without a prescription would be grouped into the non-melatonin group; therefore, the analysis may not accurately reflect this. Furthermore, the number of hospitalizations was higher than the number of people newly diagnosed with heart failure, as hospitalization records can contain a number of related diagnostic codes that may not always include the code for newly diagnosed heart failure. The researchers also lacked information on the severity of insomnia and other mental health disorders.
”Increased insomnia, depression/anxiety, or the use of other sleep aids may be associated with both melatonin use and cardiovascular risk,” Nadi said. “Furthermore, while this association we found raises concerns about the safety of this widely used supplement, our study was unable to establish a direct cause-and-effect relationship. This means that further research is needed to examine the heart safety of melatonin.”
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Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Dr. Marie-Pierre St-Onge, CCSH, FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, “Multidimensional Sleep Health: Definition and Its Impact on Cardiovascular and Metabolic Health,” is also a professor of nutrition in the Department of General Medicine at Columbia University Irving Medical Center in New York City and director of the Center of Excellence for Sleep and Circadian Rhythm Research in the Department of Medicine.
Post time: Nov-06-2025