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

Long-Term Melatonin Use and Health Risks

A review of five years of health records involving more than 130,000 adults with insomnia who used melatonin supplements for at least one year found a higher likelihood of being diagnosed with heart failure. These individuals also showed increased rates of hospitalization due to heart failure and a greater risk of death from any cause.

Study Presentation and Context

This preliminary research was presented at the American Heart Association’s Scientific Sessions 2025, held in New Orleans from November 7-10. The event is a leading platform for the latest developments in cardiovascular science, evidence-based clinical practices, and research advancements.

About Melatonin

Melatonin is a hormone naturally produced by the pineal gland that regulates the sleep-wake cycle. Its levels rise in darkness and fall during daylight. Synthetic versions of melatonin, chemically identical to the natural hormone, are commonly used as over-the-counter supplements to help with insomnia and jet lag.

Supplement Regulation and Quality Concerns

In the United States, melatonin supplements are available without government approval for quality or consistency. This leads to variability in strength and purity across different brands.

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

Author's summary: Extended melatonin supplement use for sleep may increase heart failure risks and mortality, underscoring a need for caution and further research.

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www.heart.org www.heart.org — 2025-11-03

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