It’s easy to jump to conclusions when you read a headline that suggests the buzzy sleep supplement melatonin is linked with heart failure. While recent research presented at the American Heart Association’s Scientific Sessions did find a link between long-term melatonin use and a higher risk of heart failure, the exact reason for this is muddled.
Melatonin is a hormone that your brain makes in response to darkness, according to the National Center for Complementary and Integrative Health (NCCIH). It helps to regulate your circadian rhythm (your internal clock), and can help you to fall asleep. But melatonin also comes in supplement form, which is designed to help gear your body up to go to sleep.
Melatonin use has exploded in the U.S. over the past few years, with research finding that use of the supplement quintupled between 1999 and 2018. Now, about two in every 100 people say they take melatonin supplements to help them sleep.
Doctors stress that the findings don’t mean that people who take melatonin will develop heart failure, but they do say this is a good time to check in about your own melatonin use and what it means for your health. With that in mind, here’s what the study found, plus why it should make you rethink your relationship with the supplement.
What did the study find?
For the study, which has not yet been published, researchers analyzed data from nearly 131,000 adults with an average age of 55.7 years who had been diagnosed with insomnia. Of those, 65,414 had been prescribed melatonin supplements at least once and said they took it for at least a year.
After crunching the data, the researchers discovered that people who took melatonin for 12 months or more had about a 90% higher risk of developing heart failure over five years compared to those who didn’t take the supplement. (Worth noting: Overall numbers were still low. Researchers found that 4.6% of people taking melatonin developed heart failure compared to 2.7% of those who didn’t take melatonin.)
The researchers also discovered that there was an 82% higher risk of developing heart failure in people who had at least two melatonin prescriptions filled at least 90 days apart. (In the U.K., melatonin is only available by prescription, while it’s commonly taken OTC in the U.S.)
A few more things worth pointing out: People who took melatonin were nearly 3.5 times as likely to be hospitalized for heart failure compared to those who didn’t take melatonin. People in the melatonin group were also nearly twice as likely to die from any cause during the five-year study period vs. those who didn’t take melatonin.
