Experts Urge Caution Over Nightly Melatonin Use After Study Links It to Heart Risk

Melatonin is a natural hormone produced by the brain that helps signal when it’s time to sleep. Many people turn to melatonin supplements — often sold openly as gummies or tablets — to fall asleep more easily. But recent research has prompted fresh questions about whether prolonged use might affect heart health.

A study highlighted by the American Heart Association followed more than 130,000 adults and found that people who took melatonin regularly over a long period appeared to face a higher chance of developing heart failure or dying prematurely. The researchers reported that frequent users had about a 90% greater risk compared with non-users.

The findings alarmed many who rely on nightly melatonin. NHS surgeon Dr. Karan Rajan responded on social media, urging calm and context. He stressed that the research shows an association rather than proof that melatonin directly damages the heart. Often, people with early or hidden heart disease have poor sleep and may begin using melatonin to cope, he said — meaning the supplement can be a marker of existing illness rather than its cause.

Dr. Rajan added that chronic insomnia and stress-related sleep troubles themselves raise cardiovascular risk. Because those struggling with sleep are more likely to take melatonin, the link seen in the study could reflect underlying health problems instead of the supplement triggering heart disease. In short, the study points to correlation, not causation.

He also warned that many users take doses far beyond what the body naturally produces. The human body typically makes about 0.3 milligrams of melatonin each night, while over-the-counter products often contain 3, 5 or 10 milligrams — sometimes 100 to 1,000 times the natural amount. Treating melatonin as harmless because it’s “natural” or candy-like can be misleading, he said.

Dr. Rajan’s practical advice is to avoid daily, long-term melatonin use. Use the lowest effective dose for the shortest necessary time, and consult a doctor if sleep problems persist instead of relying solely on supplements.

Health professionals also recommend simple, non-drug measures to improve sleep: keep a regular bedtime, limit phone and screen time before bed, avoid late-day caffeine, and create a calm, quiet bedroom environment.

The new findings don’t mean melatonin is unsafe for everyone, but they underscore the need for careful use. If someone needs melatonin every night to sleep, clinicians say this could signal an underlying condition that deserves medical attention.

This account draws on public medical commentary and social media discussion. The study’s claims remain under scientific review, and further research will be needed to clarify the relationship between melatonin use and heart outcomes.