Chronic insomnia patients on melatonin show elevated heart failure odds in new analysis
A preliminary study presented at the American Heart Association's Scientific Sessions found that chronic insomnia patients with long-term melatonin use had about a 90% higher risk of heart failure over five years. The study does not prove causation, but it raises safety questions about extended use of the supplement. Melatonin is widely used and often considered harmless.
The study drew on five years of electronic health records from the TriNetX Global Research Network, comparing chronic insomnia patients with documented melatonin use of at least one year against matched peers with no melatonin records. Participants with existing heart failure or other sleep medication prescriptions were excluded from the analysis.
Melatonin is a naturally occurring hormone that regulates circadian rhythms, and synthetic versions are chemically identical to the body's own. Because U.S. over-the-counter supplements are unregulated, product strength and purity can vary between brands, adding another layer of uncertainty to long-term safety assessments.
This preliminary finding could reshape how both physicians and patients approach insomnia management, particularly among older adults who may already carry cardiovascular risk factors. If confirmed by further research, it may prompt more cautious prescribing guidance and encourage patients to explore non-pharmacological sleep interventions. However, because the study does not establish causation, it should not trigger alarm or prompt anyone to abruptly discontinue melatonin without consulting a healthcare provider.