- About 16% of the world’s population lives with insomnia.
- There are a number of different methods a person may use to help them improve their sleep quality, such as taking melatonin supplements.
- Past studies show there are some potential risks to taking melatonin supplements.
- A new study reports that long-term use of melatonin supplements may be linked to a greater risk for heart failure.
Other people struggling with sleep may opt for medical treatments, including prescription medications or over-the-counter aids such as supplements of melatonin — a hormone naturally produced in the body that plays a major role in regulating the circadian rhythm.
The research is yet to appear in a peer-reviewed journal.
For this study, researchers analyzed medical data from TriNetX for almost 131,000 adults with an average age of about 56 who had been diagnosed with insomnia. About 65,000 study participants had received a prescription for melatonin at least once and reported taking it for at least one year.
At the study’s conclusion, researchers found that participants who used melatonin for more than 1 year increased their heart failure risk by 90% over 5 years, compared to those not using melatonin. And participants who had filled at least two melatonin prescriptions at least 90 days apart had an 82% greater chance of developing heart failure.
In addition, scientists discovered that study participants taking melatonin were about 3.5 times more likely to be hospitalized for heart failure and twice as likely to die from any cause over the five-year follow-up period, when compared to those not taking melatonin.
“Melatonin supplements are widely thought of as a safe and ‘natural’ option to support better sleep, so it was striking to see such consistent and significant increases in serious health outcomes, even after balancing for many other risk factors,” Ekenedilichukwu Nnadi, MD, chief resident in internal medicine at SUNY Downstate/Kings County Primary Care in New York, and lead author of the study, said in a
“Worse insomnia, depression/anxiety or the use of other sleep-enhancing medicines might be linked to both melatonin use and heart risk. Also, while the association we found raises safety concerns about the widely used supplement, our study cannot prove a direct cause-and-effect relationship. This means more research is needed to test melatonin’s safety for the heart,” Nnadi explained.
Medical News Today had the opportunity to speak with Kanika P Mody, MD, a cardiologist in the Advanced Heart Failure & Pulmonary Hypertension Center at Hackensack University Medical Center in New Jersey, who was not involved in this study, who commented that her first reactions to this new research was of surprise and concern.
“Melatonin is widely regarded by both the public and many in the medical community as a safe, ‘natural’ sleep aid, so it was striking to see a potential link to serious health issues like heart failure,” Mody explained.
“While this study shows an association and not a direct cause-and-effect relationship, the consistency and significance of the increased risks are noteworthy. It’s particularly unexpected given that some previous research has suggested potential cardiovascular benefits of melatonin, such as its antioxidant properties.”
– Kanika P Mody, MD
“This new research challenges the common practice of long-term melatonin use for chronic insomnia, for which it is not an indicated treatment in the United States,” she continued. “These findings prompt a re-evaluation of how we counsel patients about sleep aids and underscore the importance of discussing long-term supplement use.”
“My concern is that insomnia may actually be masking signs and symptoms of early heart failure in some of these cases, so this research also highlights this importance of ruling out different causes of insomnia, particularly since the treatment market for insomnia aides is not strongly regulated,” Mody added.
Mody said the next steps for this research should focus on several key areas to clarify the findings and their implications for patient care, including confirmation and causality.
“First and foremost, further research is needed to confirm these findings and to determine if there is a direct cause-and-effect relationship between long-term melatonin use and heart failure,” she detailed. “Randomized controlled trials would be the ideal next step to test melatonin’s safety for the heart.”
“If a causal link is established, research will need to explore the biological mechanism by which long-term melatonin use might increase the risk of heart failure,” Mody added. “This would be a significant shift, as much of the existing research has pointed toward melatonin’s protective cardiovascular effects.”
MNT also spoke with Yu-Ming Ni, MD, a board-certified cardiologist and lipidologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA, who was also not involved in this study.
“My first reaction to the study is that melatonin is found in multiple different formulations, including high and low doses, as well as slow release and immediate release, none of which is FDA regulated,” Ni commented.
“So, there are concerns that melatonin drug levels may be quite variable between different melatonin and supplements. It is hard to tell if the increase in heart failure is related to a specific quantity or type of melatonin. But certainly, the study is concerning, given that melatonin is not FDA regulated,” he noted.
For those who may be taking melatonin, Ni advises to strongly consider what else can be done to improve sleep quality.
“For example, many people are living with sleep apnea, and don’t know it, and mistakenly think that they need to simply take a sleep aid to help them to sleep,” he explained. “We know that sleep apnea is associated with
“I would recommend that if you have issues with sleep quality, to consult with your doctor about getting a sleep test to rule out sleep apnea,” he continued.
“What I will also say is that melatonin and high doses appear to have a paradoxical effect on sleep — in other words, you may actually have trouble falling asleep if you take too much melatonin. I usually tell my patients to cap it at 1 to 3 mg of melatonin nightly. I also instruct my patients that typically it needs to be given at least an hour or two before you try to go to sleep, because the effect of the melatonin hormone on sleepiness is slow.”
– Yu-Ming Ni, MD