Long-term Melatonin Use Linked to Negative Heart Health Outcomes
A recent review examined health records spanning 5 years for over 130,000 adults with chronic insomnia who used melatonin supplements for at least one year. The study found an increased likelihood of being diagnosed with heart failure, requiring hospitalization due to heart failure, and a higher risk of death from any cause among these users.
Study Presentation and Context
This preliminary research was presented at the American Heart Association’s Scientific Sessions 2025, held from November 7 to 10 in New Orleans. The event is a leading international forum for the latest cardiovascular research and evidence-based clinical updates.
About Melatonin
Melatonin is a hormone produced naturally by the pineal gland, playing a key role in regulating the sleep-wake cycle. Its levels rise during darkness and fall with daylight.
Synthetic melatonin supplements, chemically identical to the natural hormone, are commonly used to treat insomnia and jet lag. These supplements are widely available over the counter in many countries, including the United States.
Supplement Quality Concerns
In the U.S., over-the-counter melatonin supplements do not require government approval to verify quality and consistency. As a result, the strength, purity, and composition of melatonin products can vary significantly between 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,” says the study presentation.
Summary
The long-term use of melatonin supplements in people with chronic insomnia may be linked to increased risks of heart failure and mortality, highlighting the need for caution and further research.