If you’ve seen recent headlines warning that melatonin might cause heart failure, don’t lose sleep over them—literally.
Heart experts say the concern is premature and not supported by strong evidence.
The reports come from a preliminary study that looked at people who used melatonin for insomnia, but researchers say the findings should be interpreted with caution.
Melatonin is a hormone that your body naturally produces to help regulate sleep. Levels rise in the evening when it gets dark, signaling to your brain that it’s time to rest.
Many people take lab-made melatonin supplements to help them fall asleep faster, recover from jet lag, or adjust to time changes. It’s one of the most popular over-the-counter sleep aids in the United States.
The new study raised alarms because it found that people who took melatonin for long periods were more likely to develop heart failure. The research, presented at an American Heart Association meeting, followed adults who had insomnia and a record of takin…
Over five years, 4.6% of the long-term melatonin users developed heart failure, compared to 2.7% of those who didn’t take it.
However, cardiologists emphasize that this kind of observational study cannot prove that melatonin caused the problem. It may simply reflect the fact that people who suffer from chronic insomnia already have a higher risk of heart disease.
Dr. Pratik Sandesara, an interventional cardiologist at Emory Healthcare who was not involved in the research, said there’s no reason for patients to panic. “We should not raise the alarm and tell patients to stop taking all their melatonin,” he said. “The study shows an association, not cause and effect.”
Experts also point out that the study has important limitations. In the United States, melatonin is available without a prescription, so many Americans who use it wouldn’t show up in medical databases. That means researchers may have missed people who were taking melatonin on their own.
In addition, the study didn’t specify the doses used or the exact brands. That matters, because supplements sold in the U.S. aren’t strictly regulated by the government. The strength and purity of melatonin products can vary widely between brands.
Dr. Clyde Yancy, chief of cardiology at Northwestern University, agreed that the results should be treated as a signal for more research—not as proof of danger. “We need to study this more carefully,” he said. “The study doesn’t tell us that melatonin causes harm, only that we need better data.”
Most doctors recommend melatonin for short-term use only, such as for travel-related sleep problems or temporary insomnia. Long-term use has not been studied enough to know whether it is completely safe. “There’s no strong evidence showing that people should use melatonin indefinitely,” Yancy noted.
For those struggling with sleep, experts say the best long-term solution isn’t necessarily a pill—it’s improving sleep habits. Keeping a regular bedtime, reducing exposure to bright and blue light in the evening, and making sure your room is dark and quiet can help your body produce melatonin naturally.
“When we expose ourselves to blue light, especially from phones and computers at night, we reduce our melatonin levels,” Yancy said. “That’s just science.”
In short, the new study doesn’t mean melatonin is dangerous—but it does remind us that sleep supplements should be used wisely. Occasional use under a doctor’s guidance is likely safe for most people, but those with chronic sleep problems should focus on better sleep hygiene and talk to their healthcare provider about safer, long-term solutions.
If you care about heart health, please read studies that yogurt may help lower the death risks in heart disease, and coconut sugar could help reduce artery stiffness.
For more information about health, please see recent studies that Vitamin D deficiency can increase heart disease risk, and results showing vitamin B6 linked to lower death risk in heart disease.
The study is published in Circulation.
Copyright © 2025 Knowridge Science Report. All rights reserved.
