Long-term use of melatonin supplements to support sleep may have negative health effects

A review of five years of medical records for over 130,000 adults with chronic insomnia revealed a concerning link between long-term melatonin use and cardiovascular health issues.

Key Findings

Adults who took melatonin supplements for more than a year were more likely to be diagnosed with heart failure.
They showed higher rates of hospitalization related to heart failure.
There was an increased risk of death from any cause among these long-term users.

Study Background

The preliminary study will be presented at the American Heart Association’s Scientific Sessions 2025, held November 7–10 in New Orleans. The event serves as a major global forum for sharing new scientific discoveries and clinical practices in cardiovascular research.

Understanding Melatonin

Melatonin is a hormone produced in the pineal gland that regulates the body’s natural sleep-wake rhythm. Levels rise during the night and drop during daylight. Synthetic melatonin, chemically identical to the natural hormone, is widely used to manage insomnia and jet lag.

Public Access and Quality Control

In many countries including the United States, melatonin supplements are available over the counter. Because they do not require government approval, products can vary in strength, purity, and composition between brands.

“Long-term use of melatonin supplements was associated with a higher risk of heart failure diagnosis, hospitalization, and death from any cause in adults with insomnia.”

Author’s Summary

Regular melatonin use for sleep might increase cardiovascular risks, calling for careful consideration before long-term supplementation.

www.heart.org — 2025-11-04