Melatonin and heart failure: Long-term use of melatonin, a popular over-the-counter sleep supplement, has been linked to a higher risk of heart failure and early death in adults with insomnia, according to new research published on Monday. While the findings don’t show that melatonin directly causes heart problems, experts suggest that the need to rely on it regularly to fall or stay asleep could point to hidden heart-related issues.What Is Melatonin?Melatonin is a naturally occurring hormone that plays a key role in regulating sleep. Often called the body’s “sleep hormone,” it helps control the circadian rhythm, which is the internal clock that tells us when to sleep and wake up. The pineal gland in the brain produces melatonin, but many people now turn to melatonin supplements to improve sleep quality. According to the Cleveland Clinic, these supplements are often marketed for managing insomnia or jet lag. While melatonin can help set a natural sleep cycle, it is not meant to diagnose, treat, or prevent any medical condition. In several countries, including the United States, it is available over the counter without a prescription.Can Melatonin Lead To Heart Issues?As over-the-counter supplements are not strictly regulated, melatonin products can vary widely in their concentration and purity. This inconsistency may contribute to different long-term effects on the body. To assess the potential risks, researchers examined health data from more than 130,000 adults diagnosed with insomnia who had used melatonin for at least a year. They compared these individuals with others who also had insomnia but did not take the supplement.The results were concerning. People who used melatonin for 12 months or longer showed about a 90 percent higher risk of heart failure over a five-year period than those who did not.“Melatonin supplements are widely considered a safe and ‘natural’ solution for better sleep, so it was striking to see such strong links to serious health outcomes even after accounting for other risk factors,” said study author Ekenedilichukwu Nnadi, as quoted by The Independent.Heart failure occurs when the heart cannot pump enough oxygen-rich blood to meet the body’s needs, which can be life-threatening. The study also observed a similar rise in heart failure risk among people who had at least two melatonin prescriptions filled 90 days apart. In fact, melatonin users were found to be 3.5 times more likely to be hospitalised for heart failure compared to non-users, according to the research, which was presented at the American Heart Association’s 2025 Heart Disease and Stroke Statistics meeting but has not yet been peer-reviewed.So, Is Melatonin Safe To Consume?To understand the implications, we spoke with Dr. Khushboo Hatekar, Assistant Professor of Neurology at Dr. D.Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune. She explained that long-term dependence on melatonin often points to underlying conditions such as cardiovascular stress caused by chronic insomnia. “Insomnia itself raises blood pressure, stress hormones, and inflammation, all of which strain the heart. So, prolonged melatonin use may serve as a signal of hidden heart issues rather than being the direct cause,” she said.Dr. Hatekar also cautioned against taking melatonin regularly without medical supervision. “Most guidelines recommend melatonin for short-term use, mainly for jet lag or specific sleep disorders,” she added. However, current evidence highlights the need for more detailed clinical studies to determine whether extended use poses a cardiovascular risk.While short-term use of melatonin appears safe for most people, taking it continuously for a year or longer may increase the likelihood of heart failure and related complications. Both patients and doctors should carefully weigh the benefits and monitor heart health if the supplement is used over an extended period.