Melatonin, a widely available over-the-counter supplement often used to improve sleep, may pose more risks than previously thought. A new study analyzing health records from over 130,000 adults with insomnia reveals a significant association between long-term melatonin use (a year or longer) and an increased risk of heart failure, hospitalization for the condition, and even mortality.
What is Melatonin and Why Do People Use It?
Melatonin is a hormone naturally produced by the pineal gland in the body, playing a crucial role in regulating the sleep-wake cycle. Levels of this hormone rise during darkness, signaling the body to prepare for sleep, and decrease with the onset of daylight. Synthetic, chemically identical versions of melatonin are commonly used to treat insomnia (difficulty falling and staying asleep) and manage jet lag. Its accessibility over-the-counter in many countries, including the U.S., contributes to its widespread use.
The Study’s Findings: A Concerning Trend
Researchers examined five years of electronic health records to investigate whether long-term melatonin use affects the risk of heart failure, specifically among individuals with chronic insomnia. They compared adults with insomnia who had documented melatonin use for a year or more with a similar group who never had melatonin recorded in their medical histories. Key findings include:
- Increased Heart Failure Risk: Adults with insomnia who used melatonin long-term had approximately a 90% higher chance of developing heart failure over five years compared to non-users (4.6% vs. 2.7%).
- Higher Hospitalization Rate: Participants taking melatonin were nearly 3.5 times more likely to be hospitalized for heart failure (19.0% vs. 6.6%).
- Elevated Mortality Risk: Individuals in the melatonin group were nearly twice as likely to die from any cause compared to the non-melatonin group (7.8% vs. 4.3%) during the five-year study period.
These results were consistently observed even when considering individuals with multiple melatonin prescriptions filled at least 90 days apart.
Why These Findings Matter
Heart failure occurs when the heart struggles to effectively pump oxygen-rich blood to the body’s organs, a common and serious condition affecting 6.7 million adults in the U.S., according to the American Heart Association.
The study’s findings challenge the widespread perception of melatonin as a completely safe and “natural” sleep aid. The researchers were surprised by the consistency and significance of the increases in serious health outcomes, even after accounting for various risk factors. “I’m surprised that physicians would prescribe melatonin for insomnia and have patients use it for more than 365 days,” stated Columbia University’s Dr. Marie-Pierre St-Onge, highlighting the fact that melatonin is not officially indicated for insomnia treatment in the U.S.
Melatonin supplements may not be as harmless as commonly assumed. If our study is confirmed, this could affect how doctors counsel patients about sleep aids. – Dr. Ekenedilichukwu Nnadi
The study underscores the need for greater caution and awareness surrounding the chronic use of melatonin. While convenient and readily available, it suggests that long-term use may carry potential cardiovascular risks that warrant further investigation and careful consideration by both patients and healthcare professionals. It also emphasizes the importance of discussing any sleep concerns with a doctor, exploring alternative treatments, and avoiding long-term melatonin use without proper medical guidance
