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, s*x, 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/