Taking Melatonin Every Night May Nearly Double Heart Failure Risk

A recent study involving adults with chronic insomnia found a link between long-term melatonin supplement use and an increased risk of heart failure and early death. Melatonin is widely used in the United States, with about six million people relying on it to fall asleep faster or stay asleep longer.

The research showed that adults with insomnia who took melatonin for at least a year were much more likely to develop or be hospitalized for heart failure, or die from any cause within five years, compared to similar adults who did not take melatonin.

“Melatonin supplements may not be as harmless as commonly assumed,” says lead author Ekenedilichukwu Nnadi, MD, chief resident in internal medicine at Kings County Hospital and Downstate Health Sciences University in Brooklyn, New York.

If further studies support these findings, it may change how doctors discuss the risks and benefits of melatonin with their patients.

Study Overview

Researchers analyzed health records from a large international database of over 130,000 adults with insomnia but no previous history of heart failure. They compared those using melatonin for more than a year with a matched group who never used the supplement.

The findings reveal important safety concerns about prolonged melatonin use, especially for those with chronic sleep difficulties.

Author's Summary

Long-term melatonin supplementation in adults with insomnia is linked to a notably higher risk of heart failure and mortality, highlighting the need for careful evaluation of its use.

Everyday Health — 2025-11-06