In November 2025, the American Heart Association (AHA) reported early findings linking long-term melatonin use (≥1 year) with alarming outcomes: ~90% higher risk of heart failure ~2× higher all-cause mortality ~3.5× higher risk of hospitalization for heart failure (AHA, 2025
, Science Media Centre Spain, 2025
) For professionals in toxicology, regulatory science, or product development, this should be a red flag: