The observational study reported a higher five-year rate of heart failure among patients with recorded long-term melatonin prescriptions (4.6% vs. 2.7%), but experts emphasize it does not prove causation. Key limitations include missing over-the-counter use in countries like the U.S., lack of dosage information and variable supplement quality. Clinicians advise consulting a doctor, favoring short-term melatonin use when appropriate, and prioritizing good sleep hygiene while further research is conducted.
Don’t Panic: Study Linking Long-Term Melatonin Use to Heart Failure Is Preliminary, Experts Say
The observational study reported a higher five-year rate of heart failure among patients with recorded long-term melatonin prescriptions (4.6% vs. 2.7%), but experts emphasize it does not prove causation. Key limitations include missing over-the-counter use in countries like the U.S., lack of dosage information and variable supplement quality. Clinicians advise consulting a doctor, favoring short-term melatonin use when appropriate, and prioritizing good sleep hygiene while further research is conducted.
04:07, 08.11.2025Health
Don’t lose sleep over headlines about melatonin and heart failure
A preliminary international analysis raised questions about whether long-term melatonin use is associated with a higher rate of heart failure, but experts say the findings do not prove the supplement causes heart problems.
What the study found
Researchers who reviewed international electronic health records followed adults diagnosed with insomnia. They reported that over five years, 4.6% of patients with a melatonin prescription indicating at least one year of use developed heart failure, compared with 2.7% of insomnia patients without recorded melatonin use. The work was presented at an American Heart Association meeting but has not yet been peer-reviewed.
Important limitations
Observational study: This type of analysis can show an association but cannot prove that melatonin caused the higher heart-failure rate. Underlying insomnia or other health differences could explain the result.
Incomplete recording of use: Only some countries require prescriptions for melatonin. In the United States, melatonin is widely available over the counter, so many U.S. users would not appear in prescription records.
No dosage or product data: The study did not report how much melatonin people took. Over-the-counter supplements in the U.S. are not held to prescription-drug standards, so ingredient strength and purity can vary by brand.
“We should not raise the alarm and tell patients to stop taking all their melatonin,”
What experts recommend
Clinicians advise discussing melatonin use with your doctor. Many recommend melatonin for short-term situations such as jet lag or temporary sleep disruption, rather than indefinite nightly use. The study’s authors and outside cardiologists say the findings should prompt more rigorous, controlled research to clarify whether there is any causal link.
Improving sleep health remains essential for cardiovascular risk reduction. Practical steps include keeping the bedroom dark, limiting exposure to blue light from screens in the evening, maintaining a regular sleep schedule and addressing sleep disorders with a healthcare professional.
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