Does Taking Melatonin Increase Your Risk of Heart Problems?

Millions of people rely on melatonin as a cheap, natural sleep aid, but a new study suggests this over-the-counter supplement may be linked to an increased risk of heart problems.

The research, recently presented at the American Heart Association’s 2025 Scientific Sessions and not yet peer-reviewed, found that melatonin users had higher rates of heart failure, hospitalizations and death than non-users.

Experts emphasize, however, that the study does not prove that melatonin is the cause of these heart problems.

To better understand how melatonin might affect the heart, researchers recruited more than 130,000 adults: 65,414 who had taken melatonin for at least a year and an equal number who had not. For five years, they followed the participants and tracked new heart failure diagnoses, heart failure-related hospitalizations, and all-cause mortality.

Researchers found that melatonin users had higher levels in all categories:

• Heart failure: 4.6% of melatonin users (3,021 people) developed heart failure, compared to 2.7% (1,797 people) of the control group, an approximately 90% higher risk.
• Hospitalizations: 19% of melatonin users (12,411 people) were hospitalized for heart failure compared to 6.6% (4,309) of non-users, making them 3.5 times more likely to be hospitalized.
• All-cause mortality: Melatonin users were nearly twice as likely to die from any cause over the five-year period, compared to those who didn’t take melatonin.

The study’s lead author, Ekenedilichukwu Nnadi, MD, chief resident in internal medicine at SUNY Downstate/Kings County Primary Care in Brooklyn, noted that the findings raise important questions.

“Melatonin supplements may not be as harmless as commonly thought,” he said in a press release. “If our study is confirmed, it could affect how doctors advise patients about sleeping pills.”

Still, he and other experts said it’s far too early to conclude that the supplement harms the heart.

Because the research has not been published, more details about the study design and participant demographics are needed to better understand the implications, said Abha Khandelwal, MD, an imaging cardiologist and clinical associate professor of cardiovascular medicine at Stanford Medicine, who was not involved in the research. Health.

Joyce M. Oen-Hsiao, MD, FACC, a cardiologist and associate professor of cardiology at Yale Medicine, who was also not affiliated with the new study, added that the findings contrast with two decades of evidence suggesting that melatonin might actually benefit people with heart failure.

However, she said the new study was not “designed to prove that there is a direct relationship between melatonin consumption and increased heart failure.”

Other factors could explain the higher risk observed in melatonin users. People with insomnia often have other medical problems, like anxiety or depression, that can affect heart health, according to Oen-Hsiao. People with chronic insomnia also tend to have higher rates of obesity, be older, or have hypertension, diabetes, or limited physical activity, Khandelwal added.

Again, there is no strong evidence that melatonin causes heart problems or increases the risk of death. Still, there are plausible explanations for this, said Eman A. Hamad, MD, cardiologist and director of the Advanced Heart Failure and Transplant Program at Temple University Hospital.

Melatonin, a hormone produced by the brain, helps regulate the body’s circadian rhythm, which affects blood pressure, heart rate, and vascular tone. “Taking it chronically or in high, unregulated doses could disrupt these normal day-night patterns,” she said. Health.

Hamad also pointed out that supplements in the United States, which are largely unregulated, often contain higher doses than listed on the label. In the case of melatonin, she said, it could potentially “cause excessive drops in blood pressure or heart rate in sensitive individuals.”

Research has shown that melatonin can help reduce cholesterol, blood pressure and inflammation in the arteries, Oen-Hsiao said. Health. The supplement may also improve sleep for some people, and better sleep is consistently associated with decreased stress and higher energy, she added.

With that in mind, you don’t need to give up melatonin just yet, Oen-Hsiao noted. Most people can safely take it at the recommended dose. Ideally, start with the lowest dose available and avoid taking it every night, she advised.

If you’re concerned about potential risks, Hamad recommends making an appointment with your doctor. They can review your medical and family history, assess underlying sleep disorders and risk factors, and determine if melatonin is right for you.

“To me, this is a conclusion to proceed with caution,” she said of the new study. “Not a reason to panic, but a reason to re-evaluate chronic, unsupervised melatonin use.”