NEW ORLEANS — Prolonged use of melatonin for the treatment of insomnia was associated with an increased risk for heart failure, hospitalization, and/or all-cause mortality, an observational study showed.
Individuals with insomnia taking melatonin for a year or more had an 89% higher chance of incident heart failure over 5 years than those who didn’t take it. They were also 3.5 times more likely to be hospitalized for the condition, the preliminary findings, which are not yet peer reviewed, suggested.
“Long-term nightly use may not be as risk-free as we assumed,” lead author Ekenedilichukwu Nnadi, MD, chief resident in internal medicine at SUNY Downstate/Kings County Primary Care, Brooklyn, New York, told Medscape Medical News.
While the study does not show causation and short-term use doesn’t appear to raise cardiac risks, “if you’re using it indefinitely, especially if you have heart disease or risk factors, it’s something worth discussing with your physician,” Nnadi said.
The findings will be presented on November 10 at the American Heart Association (AHA) Scientific Sessions 2025.
Challenging Previous Findings
Previous research suggested melatonin may be beneficial for cardiometabolic health, in part due to its antioxidant properties. Other studies have indicated taking melatonin supplements before sleep can lower blood pressure.
In the US, melatonin is available over the counter and marketed as a low-cost sleep aid. However, the investigators highlighted that robust data on its long-term cardiovascular effects were lacking.
The investigators reviewed data from the TriNetX Global Research Network database of 130,828 adults (average age, 55.7 years; 61% women) with a diagnosis of insomnia. Half of participants were prescribed melatonin at least once and reported taking it for at least 12 months.
Patients in the control group were not prescribed the sleep aid and were matched to the melatonin group on 40 different factors, including age, sex, race or ethnicity, heart and nervous system diseases, medications …
