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

Long-term Melatonin Use and Health Risks

A recent review analyzed five years of health data from over 130,000 adults with insomnia who used melatonin supplements for at least one year. The findings indicated a higher likelihood of being diagnosed with heart failure, increased hospitalizations for this condition, and a greater risk of death from any cause among chronic insomnia sufferers using melatonin.

Study Presentation and Context

This preliminary study will be presented at the American Heart Association’s Scientific Sessions 2025, held in New Orleans from November 7 to 10. The event is a leading global forum for sharing advances in cardiovascular science and evidence-based clinical practices.

Melatonin: Natural Role and Supplement Use

Melatonin is a hormone produced naturally by the pineal gland in the brain, playing a key role in regulating the sleep-wake cycle. Its levels rise at night and fall during daylight. Synthetic melatonin supplements, chemically identical to the natural hormone, are commonly used to treat insomnia and jet lag.

Availability and Regulatory Notes

Melatonin supplements are widely sold over the counter in many countries, including the U.S. However, in the U.S., these supplements are not subject to government approval for quality and consistency, resulting in variability among different brands in terms of strength and purity.

“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,” according to the study presented at the American Heart Association’s Scientific Sessions 2025.

Overall, while melatonin supplements are popular for sleep support, prolonged use may carry significant cardiovascular risks that warrant caution.

Author’s summary: Prolonged melatonin supplementation for insomnia may increase heart failure risk and mortality, emphasizing the need for careful use and further study.

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www.heart.org www.heart.org — 2025-11-04

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