Common Supplement Shows Concerning Link to Heart Failure

New research into a widely used sleeping aid has raised concerns among scientists about its long-term use. An analysis of adults with insomnia, which is yet to be peer-reviewed, found that those prescribed melatonin for over a year had higher risks of heart complications.

Study Findings

Among more than 130,000 adults from various countries, individuals using melatonin long-term had an 89% increased risk of heart failure within five years. Additionally, their risk of dying from any cause was twice as high compared to those not prescribed melatonin.

Context and Cautions

The findings are preliminary and do not alter current health guidelines. This does not definitively prove melatonin — the fourth most popular natural product among US adults — is causing these adverse effects.

What the results do suggest is that longer-term uses of melatonin need to be studied further to ensure they are safe.

Melatonin is generally considered safe and well-tolerated for short-term use (about 1 to 2 months) in individuals who are not pregnant or breastfeeding. However, research on its effects beyond this timeframe is limited, a gap experts believe should be addressed as melatonin use continues to rise.

Presentation of Research

This new study was presented at the American Heart Association's Scientific Sessions.

Related Research

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ScienceAlert — 2025-11-07