Long-Term Melatonin Use Linked to Increased Heart Failure Risk

Research indicates that long-term use of melatonin supplements may be associated with an increased risk of heart failure. A recent study found that adults with chronic insomnia who took melatonin for more than a year had a **90% higher chance** of developing heart failure over the subsequent five years compared to those who did not use the supplement. Additionally, melatonin users were over three times more likely to be hospitalized for heart failure and approximately twice as likely to die from any cause.

Despite these alarming statistics, experts caution against hastily discontinuing melatonin as a sleep aid. The study, which analyzed electronic medical records of over **130,000 adults** through the **TriNetX Global Research Network**, has notable limitations and has not yet undergone peer review. It will be presented at the **American Heart Association’s Scientific Sessions 2025** meeting scheduled for **November 7-10, 2025**.

Dr. Ekenedilichukwu Nnadi, the lead researcher and chief resident in internal medicine at **SUNY Downstate/Kings County Primary Care** in Brooklyn, remarked, “While the association we found raises safety concerns about the widely used supplement, our study cannot prove a direct cause-and-effect relationship.” He emphasized the need for further research to evaluate melatonin’s safety for cardiovascular health.

Understanding Melatonin and Its Uses

Melatonin is a hormone produced naturally by the pineal gland in response to darkness, aiding the body in preparing for sleep. The melatonin found in supplements can be derived from animal sources or synthesized chemically. In the **United States**, melatonin is sold as a dietary supplement, which means manufacturers are not subject to the stringent safety regulations enforced by the **U.S. Food and Drug Administration** for pharmaceuticals. This can lead to variations in the potency of melatonin supplements, with some containing more of the active ingredient than indicated.

Chronic insomnia, affecting approximately **10% of the global population**, is characterized by difficulty falling or staying asleep for more than **30 minutes** multiple times a week over a three-month period. This condition can severely impact memory, energy levels, mood, cognitive functions, and overall quality of life.

Limitations of the Study and Expert Opinions

The research highlighted several critical limitations. Notably, the study included patients from countries where melatonin requires a prescription, such as the **United Kingdom**, alongside those from locations like the **United States**, where it does not. This may skew the control group, potentially including individuals who used melatonin without documented records. Dr. Carlos Egea, president of the **Spanish Federation of Sleep Medicine Societies**, noted that the absence of information regarding the severity of participants’ insomnia and any existing mental health conditions also complicates the findings.

Insomnia has been linked to an elevated risk of heart conditions, including heart attacks and strokes, suggesting that disrupted sleep patterns may contribute to cardiovascular health risks. Additionally, the lack of detailed data on melatonin dosage further clouds the study’s conclusions.

The **Council for Responsible Nutrition**, a trade association for the dietary supplement industry, stated, “Decades of consumer experience and multiple clinical studies indicate that low-dose, short-term supplementation is safe for healthy adults when used as directed.” They also emphasized the need for more comprehensive studies to clarify the relationship between melatonin use and heart health.

Guidelines for Melatonin Use

Many individuals turn to melatonin for sleep issues, whether short- or long-term. However, the supplement can lead to side effects, including headaches, nausea, dizziness, and disorientation. Dr. Marie-Pierre St-Onge, director of the Center of Excellence for Sleep & Circadian Research at **Columbia University Irving Medical Center**, advises individuals to consult their healthcare provider before using melatonin.

She emphasized the importance of obtaining a proper diagnosis for sleep difficulties and exploring appropriate treatment options. Healthy sleep practices, such as minimizing light exposure and ensuring a conducive sleeping environment, can significantly improve sleep quality. If melatonin supplementation is considered, experts recommend seeking pharmaceutical-grade products verified by independent testing organizations.

In conclusion, while recent findings raise important questions about the long-term safety of melatonin, further research is necessary to establish a clearer understanding of its effects on heart health.