Observational Study Highlights Potential Risks
A recent large-scale study presented at the American Heart Association conference found that adults with chronic insomnia who used melatonin supplements for 12 months or longer faced significantly higher risks of heart-related problems. Over a five-year period, individuals taking melatonin had about a 90% higher chance of developing new-onset heart failure compared to insomnia patients not using the supplement (4.6% vs. 2.7%). Those who filled multiple prescriptions spaced 90 days apart had an 82% increased risk, and hospitalization rates for heart failure were nearly 3.5 times higher in the melatonin group.
Mortality and Health Implications
The study also reported that all-cause mortality among long-term melatonin users was almost double that of non-users (7.8% vs. 4.3%). While these findings are concerning, researchers emphasize that the results indicate an association, not causation. The data were drawn from electronic health records, focusing on patients with insomnia who received prescribed melatonin, and may not fully capture over-the-counter usage or dosage differences.
Cautions and Recommendations
Experts note that prolonged melatonin use might reflect more severe insomnia, which itself can be a cardiovascular risk factor. Limitations include potential confounding factors, lack of detailed dosage information, and preliminary nature of the study, which has not yet undergone full peer review. Physicians advise individuals using melatonin long-term—especially those with heart risk factors—to consult their healthcare providers. Short-term use may still be appropriate, but extended nightly supplementation warrants careful evaluation.
