Melatonin supplements are widely accessible in many countries, varying in potency and purity among different brands. Despite the common belief that melatonin, a hormone naturally produced in the body to regulate sleep patterns, is harmless, researchers have identified a concerning potential risk.

The American Heart Association’s latest study revealed that prolonged use of melatonin supplements could have adverse effects on overall health. Individuals consuming melatonin for at least 12 months were found to have a higher likelihood of developing heart failure, requiring hospitalization for the condition, or experiencing mortality from any cause.

While the study did not conclusively link the supplements to these cardiac issues, the researchers emphasized the safety concerns raised and called for further investigation into melatonin’s impact on cardiovascular health. Lead researcher Ekenedilichukwu Nnadi, M.D., highlighted the need for confirmation of the study’s findings to potentially change how healthcare professionals advise patients on sleep aids.

The study analyzed five years of medical records of adults with chronic insomnia who had been using melatonin for over a year. Comparisons were made with similar individuals suffering from insomnia but not using melatonin, excluding those on other sleep medications or with prior heart failure diagnoses.

Results showed that adults using melatonin for insomnia treatment for a year or longer had a 90% higher risk of heart failure over five years compared to non-users. Those with multiple melatonin prescriptions filled at least 90 days apart faced an 82% increased risk of heart failure.

Additionally, individuals taking melatonin were almost 3.5 times more likely to require hospitalization for heart failure and nearly twice as likely to die from any cause within the five-year period compared to non-users. The study noted limitations, such as the availability of melatonin by prescription in the UK versus over-the-counter in the US, potentially impacting the classification of supplement users.

Furthermore, the researchers lacked data on the severity of insomnia and the presence of other mental health conditions among the participants.