Overview
- An American Heart Association presentation using TriNetX records of more than 130,000 adults with insomnia found yearlong melatonin users had about 90% higher heart failure incidence, 3.5 times higher hospitalization for heart failure, and nearly double all-cause mortality over five years.
- Lead author Ekenedilichukwu Nnadi said melatonin “may not be as harmless as commonly assumed” and suggested confirmation could change how clinicians counsel patients about sleep aids.
- Columbia University sleep researcher Marie‑Pierre St‑Onge urged caution with chronic use, noting melatonin in the U.S. is sold over the counter with variable strength and purity.
- The study is preliminary and not peer‑reviewed, with limitations that include reliance on medical-recorded exposure, international prescribing differences, and unmeasured factors such as insomnia severity or psychiatric conditions.
- Separately, German testers at Öko‑Test rated 12 of 19 European melatonin sprays “poor” and four “inadequate,” reporting frequent dose deviations from labels and advising medical consultation and short-term use alongside basic sleep hygiene.