11/05/2025
This new study from American Heart Association’s Scientific Sessions 2025 just dropped some eye-opening data on melatonin—a popular OTC sleep aid—and its potential ties to heart health. Let’s break it down factually, with context.
In a retrospective analysis of 130,828 adults (avg age 55.7, 61% women) with chronic insomnia, those using melatonin for at least 12 months had a ~90% higher risk of developing heart failure over 5 years compared to non-users (4.6% vs. 2.7% incidence). They were also nearly 3.5x more likely to be hospitalized for heart failure (19% vs. 6.6%) and almost 2x more likely to die from any cause (7.8% vs. 4.3%). The researchers validated this with a sensitivity analysis requiring at least two prescriptions filled 90+ days apart, showing an 82% increased risk.
Melatonin, a synthetic version of our body’s natural sleep hormone, is widely used for short-term sleep issues but isn’t FDA-approved for chronic insomnia. This study, led by Ekenedilichukwu Nnadi, MD, from SUNY Downstate, used 5 years of electronic health records. Participants were matched on 40 factors (age, sex, comorbidities, BMI, etc.) to minimize bias, excluding those with prior heart failure or other sleep meds. Heart failure affects ~6.7M US adults , and with melatonin’s unregulated status in the US, this highlights a data gap on long-term CV safety.
This shows association, not causation—melatonin might not cause heart issues; it could be a red flag for underlying factors like severe insomnia or unmeasured confounders (e.g., depression, anxiety severity). Data relies on prescriptions, so OTC users in the US may be undercounted as “non-users.” Hospitalization codes could inflate diagnoses, and the abstract lacks full clinical nuance. Bottom line: Don’t panic—short-term use is likely fine for most, but chat with your doc for chronic needs. More RCTs needed.
Check out my simple sleepy mocktail recipe for natural sleep support for a natural melatonin alternative that I reccomend for my telehealth patients:
https://drwillcole.com/what-science-says-about-the-sleepy-girl-mocktail/
