Reese Freireich, senior advertising/public relations major, shops in CVS for melatonin on Tuesday.
Erika Ryan
A new preliminary study presented Monday at the American Heart Association’s 2025 Scientific Sessions suggested that long-term melatonin use could be linked to increased heart failure and higher mortality rates among people with chronic insomnia.
While the findings may not prove that melatonin is the direct cause of heart problems, they are starting discussions about the safety of one of the most popular over-the-counter sleep aids.
In the study, researchers analyzed data from adults who have chronic insomnia. They found that those who take melatonin over an extended period of time had higher rates of heart failure and death from all causes compared to non-melatonin users.
The study has not yet been peer-reviewed, and experts caution that the study’s results are observational, meaning they can show a correlation, not a direct cause-and-effect relationship.
However, the findings still draw attention to how “natural” sleep supplements like melatonin are often perceived as safe alternatives to prescription medications.
Pedro Catalunha, a nurse at Memorial Regional Hospital in Hollywood, said that many pharmacy shoppers may be unaware of what goes into their medications.
“Many people believe when medications are sold over the counter and labeled as natural, it must be harmless,” Catalunha said. “But natural doesn’t always mean risk-free, especially when it’s long-term usage or without medical guidance.”
Melatonin, a hormone naturally produced by the brain to regulate the sleep-wake cycle, has become a go-to remedy for those who struggle with sleep.
Reese Freireich, a senior public relations and advertising major, has been a melatonin user for a year.
“Five out of seven nights of the week I use melatonin,” Freireich said. “I started using the melatonin gummies and now also use a spray because I had trouble falling asleep and staying asleep. I wanted to improve my overall quality of sleep.”
The new study adds to growing scrutiny over the long-term effects of melatonin. Past studies have raised concerns about inconsistent dosage, interactions with other medications and the impact on hormone regulation when taken in large amounts or over long periods.
However, contrary to the recent study, Freireich has not experienced negative effects.
“I personally haven’t noticed any changes when it comes to using melatonin,” Freireich said. “I do notice, though, the more I take it, the less effective it becomes. I feel like I’m able to withstand i,t and the quality isn’t as good as I first started using it.”
While experts agree that occasional, short-term melatonin use is generally considered safe, they emphasize that people with chronic insomnia should talk with their health care provider before using it regularly.
Flavia Heiderick, a nurse at AdventHealth Celebration, recommends her patients use precautions before taking the medication.
“The precautions I recommend as a nurse are to start at the lowest dose possible, like 0.5 milligrams as needed thirty minutes before bedtime,” Heiderick said. “Most importantly, melatonin should be used with a healthy nighttime routine. Lowering light brightness and minimizing noise levels in the environment. It is also helpful when used with sleep sounds and aromatherapy.”
The researchers behind the study stressed that more investigation is needed to confirm their findings and to understand the biological mechanisms that might explain the link between melatonin and heart health. For now, the message is one of caution rather than alarm.
“Using melatonin regularly can be dangerous,” Heiderick said. “Use only when instructed by your doctor. It can interact with other heart medications and impede others from having their full effect. Melatonin has been linked in recent studies to worsening heart failure. It’s imperative your doctor is aware of all supplements you are taking that can interact with your medications.”