Long-term Use of Melatonin Supplements May Harm Health
A review of five years of health records involving over 130,000 adults with insomnia who had taken melatonin supplements for at least one year found an increased likelihood of being diagnosed with heart failure, needing hospitalization for heart failure, and a higher risk of death from any cause.
Study Overview
This preliminary study will be presented at the American Heart Association’s Scientific Sessions 2025, held from November 7-10 in New Orleans, a major event for sharing advances in cardiovascular science.
Role of Melatonin
Melatonin is a hormone naturally produced by the pineal gland that regulates the sleep-wake cycle. Its levels rise during darkness and fall in daylight.
Use of Synthetic Melatonin
Synthetic melatonin, chemically identical to the natural hormone, is commonly used to treat insomnia and jet lag. These supplements are available over the counter in many countries, including the U.S.
Supplement Regulation
In the United States, over-the-counter melatonin supplements do not require government approval for quality or consistency, leading to variations in strength and purity among different brands.
"Long-term use of melatonin supplements, often used to promote sleep and address insomnia, was associated with a higher risk of heart failure diagnosis, heart failure hospitalization and death from any cause in chronic insomnia."
Author's summary: Prolonged melatonin supplement use for insomnia may increase heart failure and mortality risks, highlighting the importance of cautious use and quality control.