Long-Term Melatonin Use Linked to 90% Increased Heart Failure Risk in Insomnia Patients

A large study analyzing over 130,000 adults with chronic insomnia found that long-term use of melatonin supplements is associated with a significantly increased risk of heart failure and higher mortality rates. Melatonin users were about 90% more likely to develop heart failure and nearly twice as likely to die from any cause within five years compared to non-users. Additionally, those taking melatonin were three to 3.5 times more likely to be hospitalized for heart failure. Researchers caution that melatonin may not directly cause heart problems but could indicate underlying cardiovascular issues such as high blood pressure or inflammation linked to insomnia. The study, presented at the American Heart Association’s Scientific Sessions 2025, underscores the need for further research into the long-term safety of melatonin, which is widely available over the counter and largely unregulated. Experts advise that melatonin should not be used chronically without medical guidance, as its safety profile remains uncertain.