Study Finds Link Between Long-Term Use of Melatonin and Heart Failure Risks

Concerns come as poison centers have seen an increase in child melatonin poisoning reports in recent years.

According to the findings of a new study, taking melatonin for longer than one year has been linked to a nearly 90% increase in a person’s risk of suffering heart failure.

In a press release issued on November 3, the findings were cited as being scheduled for presentation at the American Heart Association’s Scientific Sessions 2025 later this week, warning that the long-term use of melatonin may increase risks of hospitalization from heart failure, and that people using melatonin for longer than one year have double the risk of dying from any cause.

Heart failure occurs when the heart is unable to pump enough oxygen-rich blood to meet the body’s needs, leading to reduced organ function and potentially serious health complications. According to the American Heart Association’s 2025 Heart Disease and Stroke Statistics, heart failure affects 6.7 million adults in the U.S.

Melatonin Poisoning Concerns

Melatonin is a hormone naturally produced by the pineal gland. It helps regulate the body’s circadian rhythm, or sleep-wake cycle, with levels naturally increasing during darkness and decreasing during daylight. Synthetic versions of melatonin are used in supplements to treat insomnia and jet lag and are widely considered a natural option to support sleep.

Supplements are available over the counter (OTC) in the U.S., even though some countries require a prescription. Because a prescription is not required in the United States, melatonin is not regulated by the U.S. Food and Drug Administration (FDA).

Recent years have seen a large number of melatonin poisoning cases among young children. In 2024, data from the U.S. Centers for Disease Control and Prevention indicated more than 11,000 children were treated in emergency rooms in the U.S. for accidental melatonin ingestions. The data indicates melatonin poisoning among children increased six-fold over the past decade.

In addition, research from 2023 warned many of the supplements’ gummy forms contain levels of melatonin that are higher than indicated on the packaging. In some cases, the supplements contained more than 350% of what was listed on the label.

Melatonin Heart Failure Risks

For the new study, researchers from SUNY Downstate/Kings County Primary Care in Brooklyn, New York examined long-term use of melatonin. Led by Dr . Ekenedilichukwu Nandi, they reviewed medical records for 130,000 adults using data from a large international database.

The research team examined five years of electronic health records for adults with chronic insomnia who had melatonin use in their health records and used the supplement for more than one year. Those patients were matched with others who also had insomnia but had not used melatonin.

Overall, the data suggests that long-term melatonin use is associated with significantly higher risks of heart failure, hospitalization and death from any cause.

• 90% higher risk of heart failure: Individuals using melatonin had nearly double the risk of developing heart failure over five years compared with non-users.
• 82% greater risk among frequent users: Patients who filled two melatonin prescriptions within 90 days were 82% more likely to suffer heart failure.
• 3.5 times higher likelihood of hospitalization: People taking melatonin were 3.5 times more likely to be hospitalized for heart failure than those not using the supplement.
• Higher hospitalization rates overall: About 19% of melatonin users were hospitalized for heart failure, compared to under 7% of non-users.
• Nearly double the overall mortality risk: Melatonin users were almost twice as likely to die from any cause compared with non-users.

According to researchers, the findings of the study do not prove melatonin causes heart problems, and it did have some limitations. Researchers only used patient health records to examine the correlation, but many countries, including the U.S., do not require a prescription for melatonin. As a result, some OTC melatonin takers may have been included in the non-use group.

Researchers said the findings may affect how doctors counsel patients about insomnia and what sleep aids to take.

The study will be presented at the American Heart Association’s Scientific Sessions 2025, which is scheduled to be held from Nov 7 through 10 in New Orleans. Research presented at conferences is considered preliminary until published in a peer-reviewed journal.

Sign up for more health and legal news that could affect you or your family.