Archive · 8 Nov 2025
Study Questions Melatonin's Link to Heart Health, Experts Urge Caution
Some scientists looked at health records for people who took a sleep helper called melatonin for a long time.
They noticed that a few more of these people got a heart problem called heart failure than people who had trouble sleeping but didn't take melatonin.
But other doctors say this study doesn't really prove that melatonin caused the heart problem.
It's like saying if you eat ice cream and then get a sunburn, the ice cream must have caused the sunburn – it's more likely the sun caused it.
These doctors think the people taking melatonin might have had other issues that led to the heart problem.
They also point out that melatonin is a natural hormone that helps us sleep, and it's usually okay for a short time, like after a long plane trip.
They advise not to worry too much about the study yet, and it's always best to talk to your own doctor if you have questions about taking medicine or supplements.
It's also important to try to sleep well by having a dark room and a regular bedtime.
A preliminary study suggested a possible link between long-term melatonin use and an increased risk of heart failure.
Experts caution that the observational study cannot prove melatonin causes heart failure and advise against stopping use based on these findings.
Melatonin is a naturally occurring hormone that regulates sleep, and lab-produced versions are often used for insomnia or jet lag.
Limitations of the study include its observational nature, lack of dosage information, and varying global regulations on melatonin.
Doctors generally recommend melatonin for short-term use and advise patients to discuss concerns and practice good sleep hygiene with their healthcare providers.
- Who
- Experts including Dr. Pratik Sandesara (Emory Healthcare) and Dr. Clyde Yancy (Northwestern University), and individuals diagnosed with insomnia.
- What
- A preliminary study raised questions about the link between long-term melatonin use and heart failure, sparking expert commentary urging caution and emphasizing the limitations of the study.
- When
- Recently, concerning a study that tracked patients over five years and is being presented at an American Heart Association meeting.
- Where
- The study used international electronic health records; experts are from U.S. healthcare institutions (Emory Healthcare, Northwestern University).
- Why
- To investigate potential links between melatonin use and heart health and to provide context and guidance to the public amidst concerning headlines.
Concerns Raised by New Study
Expert Counterpoints and Recommendations
Study Findings vs. Causation
Concerns Raised by New Study
A preliminary study using international health records showed a higher incidence of heart failure in chronic melatonin users compared to those with insomnia but no recorded melatonin use.
Expert Counterpoints and Recommendations
Experts state that observational studies cannot prove causation and that the observed link may be due to underlying insomnia, not melatonin itself. They emphasize not to stop taking melatonin based on this preliminary, un-peer-reviewed study.
Melatonin Accessibility and Dosage
Concerns Raised by New Study
The study used prescription data, which may not accurately reflect melatonin use, especially in countries like the U.S. where it's over-the-counter. Dosage information was also not included.
Expert Counterpoints and Recommendations
Variations in supplement ingredients and the lack of government approval for U.S. supplements are noted. Experts suggest that a lack of recorded usage doesn't mean it wasn't used and highlight the unreliability of such data for definitive conclusions.
Long-Term Use and Alternatives
Concerns Raised by New Study
The study raises questions about the safety of long-term melatonin use.
Expert Counterpoints and Recommendations
While the study doesn't prove long-term use is dangerous, experts also state there's no evidence for indefinite use. They recommend discussing melatonin use with doctors, generally advising it for short-term situations, and promoting better sleep hygiene as a fundamental solution.
- What is Melatonin
- A hormone naturally produced by the body that regulates sleep cycles, increasing in response to darkness to trigger drowsiness.
- New Study Focus
- Examined international electronic health records of adults with insomnia and a melatonin prescription for at least a year.
- Study Findings (Preliminary)
- Over five years, 4.6% of chronic melatonin users developed heart failure compared to 2.7% of insomnia patients without recorded melatonin use.
- Study Limitations
- Observational study (cannot prove causation), varying prescription requirements for melatonin globally, U.S. melatonin being over-the-counter and un-peer-reviewed, lack of dosage information, and potential variation in supplement ingredients.
- Expert Recommendations
- Do not stop taking melatonin based on this preliminary study. Consult doctors for advice, consider short-term use (like for jet lag), and practice good sleep hygiene (e.g., dark room).
