Overview
- Among 130,828 adults with chronic insomnia, those with at least 12 months of recorded melatonin use had a 4.6% five‑year rate of incident heart failure versus 2.7% in matched nonusers.
- Long‑term users were 3.5 times more likely to be hospitalized for heart failure (19.0% vs. 6.6%) and nearly twice as likely to die from any cause (7.8% vs. 4.3%) over five years.
- The analysis drew on de‑identified records from the TriNetX Global Research Network and excluded people with prior heart failure or prescriptions for other sleep medicines.
- Authors and independent experts emphasize the study shows association rather than causation, noting unmeasured factors such as insomnia severity, mental health conditions, or other sleep aids could explain the link.
- Because many people buy melatonin over the counter in the U.S., exposure may be undercounted, and experts advise discussing long‑term use with clinicians as further peer‑reviewed and randomized research is pursued.