Researchers Say Melatonin Use Could Be Linked to Heart Failure

If you've never heard of it before, melatonin is a popular supplement that is sold as a "natural" sleep aid in stores around the world. It works by replicating the hormone that helps regulate the human circadian rhythm, making it easier to fall (and sometimes stay) asleep.

The pill is a favorite among people who are looking for a little extra help when it comes to catching zzzzz's, but who don't want to take the next step by taking a stronger sleep aid.

And while it's usually touted as being perfectly safe for most adults, researchers involved in one study say that there is evidence linking melatonin to heart failure. This news may be scary for some, especially those who rely on the supplement to ensure they're getting enough shut-eye each night.

So, should you discontinue taking your evening melatonin supplement because of the risk of heart failure? Keep reading to learn more about what the study says and what experts are suggesting.

Researchers working on a study about the long-term effects of melatonin say that long-term use of the supplement is associated with a higher risk of heart failure.

The findings were shared ahead of the American Heart Association's Scientific Sessions conference on Nov. 3, 2025. In the press release that ran the week before the event, researchers said that people who used melatonin for a year or more had a 90 percent higher chance of experiencing heart failure over a five-year span.

Additionally, the press release notes that the study participants who had been taking melatonin were almost 3.5 times more likely to be hospitalized, and they were almost twice as likely to die within that five-year span from any cause, even those not directly tied to heart failure.

Of course, it's important to note that this study has not been peer-reviewed as of the time of publication. Additionally, the study was conducted in both the U.S. and the U.K., where melatonin dosages differ.

Of course, the next question anyone who currently uses the supplement is likely to ask is whether or not it is safe to continue to do so.

Dr. Ekenedilichukwu Nnadi, the lead research author on the study, addressed that very question in a small part of the press release, saying that while the association between melatonin use and heart failure is concerning, they cannot yet directly tie the supplement to the increased risk of heart failure.

“This means more research is needed to test melatonin’s safety for the heart,” Dr. Nnadi said in the statement, which notes that these findings will be presented during the American Heart Association's Scientific Sessions 2025 meeting, which is scheduled to happen the week of Nov. 10.

It's likely that experts will have more to say about the topic once the bulk of the study's findings are shared at the event, which will likely spark additional research and commentary from experts.

This article is not meant as a substitute for medical advice. If you have questions about the safety of taking melatonin to help you fall asleep, you should contact your healthcare provider directly for more information.