“To sleep, perchance to dream” –
Nov. 5, 2025 – People who regularly used melatonin supplements for at least a year were found to have a higher likelihood of being diagnosed with heart failure, being hospitalized for heart failure, or dying from any cause compared with those who did not use the supplement. Melatonin is a hormone produced naturally by the pineal gland in the brain, where it helps control the body’s internal clock and the cycle of sleep and wakefulness. Levels rise at night and drop during the day. Synthetic melatonin, which is chemically identical to the natural hormone, is commonly taken to help with insomnia (difficulty falling and/or staying asleep) and jet lag. The supplement can be purchased without a prescription in many countries, including the United States. However, because over-the-counter products in the U.S. are not regulated, the amount and purity of melatonin can differ significantly between brands.
For this research, scientists reviewed electronic health records and grouped participants according to their melatonin use. Individuals who had documented use of melatonin for one year or longer were placed in the “melatonin group.” Those who had no record of melatonin use in their medical files were categorized as the “non-melatonin group.”
