Preliminary Study Links Long-Term Melatonin Use to Higher Heart Failure Risk

Preliminary research presented at the American Heart Association's Scientific Sessions 2025 (reported on August 29, 2026) indicates that people with chronic insomnia who used melatonin long-term had approximately a 90% higher risk of developing heart failure over five years. The findings do not establish a causal link but raise questions about the long-term safety of this widely used sleep supplement.