Concerns Over Long-Term Melatonin Use
A widely used supplement in the US, melatonin, is raising some eyebrows, according to recent research.
Marketed as a safe choice for sleep, melatonin is a hormone supplement that anyone can purchase over the counter, often without a second thought. However, initial findings have prompted researchers to consider the implications of prolonged use.
A recent study involving adults with insomnia revealed a possible association between long-term melatonin prescriptions—over a year—and an increased risk of heart complications.
In an analysis of more than 130,000 adults across various countries, individuals on long-term melatonin experienced higher rates of heart failure and mortality compared to those who were not. Specifically, those taking the supplement for more than a year had an 89% increased risk of heart failure over five years and were nearly twice as likely to die from any cause.
It’s important to note that the research hasn’t undergone peer review yet and was shared last November at the American Heart Association’s Scientific Sessions.
These results don’t alter current health guidelines, nor do they conclusively prove that melatonin—considered the fourth most popular natural supplement in the U.S.—is the cause of serious health issues. However, they do call for more thorough investigations on its long-term effects.
Typically, melatonin is seen as safe for short-term use, which encompasses about 1 to 2 months, particularly for people who aren’t pregnant or nursing. Yet, to some researchers, the scarcity of studies examining extended use raises concerns, especially given its growing popularity.
“Melatonin supplements may not be as harmless as commonly assumed,” stated medical scientist Ekenedilichukwu Nnadi from SUNY Downstate/Kings County Primary Care.
This supplement mimics a hormone that the brain produces naturally to regulate the body’s internal clock, potentially aiding those who struggle to fall asleep or stay asleep.
In both the US and many other countries, melatonin is available over the counter, allowing individuals to take it without any medical consultation regarding proper dosage or duration.
While some older studies hint at the safety of long-term use, comprehensive data remains limited. In the recent analysis, Nnadi and his team applied electronic health records from adults in the US and other countries, including the UK—where melatonin is prescription-only.
A secondary assessment showed that individuals taking melatonin for over a year faced nearly 3.5 times the risk of being hospitalized for heart failure than those not using it. Additionally, mortality risk rose from 4.3% to 7.8% between the two groups.
Nnadi expressed the concern that while melatonin is widely accepted as a safe and “natural” sleep aid, the significant health risks observed in the study were surprising, even after accounting for various other risk factors.
These findings warrant careful interpretation due to a notable methodological limitation: the study did not directly survey participants about their melatonin consumption. Instead, it relied on prescription records to gauge usage. Consequently, the control group—those not prescribed melatonin—might include individuals in the US who purchased it without a prescription.
Carlos Egea, the President of the Spanish Federation of Sleep Medicine Societies, noted these concerns, arguing for the need of more rigorous studies with control groups to better understand melatonin’s safety.
Even short-term melatonin use can present risks that many may be unaware of.
For example, reports of non-fatal melatonin overdoses in children in Australia have sparked inquiries regarding the safety of this supplement among younger populations.
Despite being derived from a natural hormone, melatonin may not be entirely without risks. “If our study is confirmed, this could influence how healthcare providers discuss sleep aids with patients,” Nnadi mentioned.
The findings were shared at the American Heart Association’s Scientific Sessions.
