Silent Risk: Long-Term Melatonin Use May Double the Chances of Heart Failure

A recent medical investigation has raised new concerns about the safety of prolonged melatonin use. The hormone — widely consumed as a natural sleep aid — may significantly increase the risk of heart failure, hospitalizations, and even death among adults suffering from chronic insomnia.

Researchers analyzed electronic health records from more than 130,000 adults diagnosed with insomnia, comparing those who took melatonin consistently for at least one year with those who did not. The findings were alarming: individuals who used the supplement for 12 months or longer were about 90% more likely to develop heart failure over a five-year period (4.6% versus 2.7%).

The risk extended beyond diagnosis. Participants who took melatonin long-term were 3.5 times more likely to be hospitalized for heart failure and had nearly double the overall mortality rate compared to non-users (7.8% versus 4.3%).

These findings challenge the widespread perception that melatonin is a completely safe, natural remedy for sleep disorders. While it is sold over the counter in many countries and marketed as a harmless hormone supplement, the evidence suggests that its effects on the cardiovascular system may be more complex than previously believed.

Experts caution, however, that the study does not prove a direct cause-and-effect relationship. The association could reflect underlying factors linked to insomnia itself — such as stress, metabolic issues, or pre-existing cardiovascular disease — rather than melatonin being the sole culprit.

Still, the data point to a potential connection that deserves closer scrutiny. One of the study’s lead physicians emphasized the need for more comprehensive clinical trials to clarify the risks: “We should not assume that something is safe just because it’s natural or available without a prescription.”

Neurologists and sleep specialists echo this concern, reminding patients that melatonin should be used with medical supervision. Short-term use is generally well tolerated, but prolonged consumption may disrupt the body’s circadian rhythm and lead to side effects like dizziness, morning grogginess, headaches, and hormonal imbalance.

The new findings serve as an important reminder: “natural” does not automatically mean “risk-free.” As millions of people around the world turn to melatonin to combat sleeplessness, experts urge a more cautious approach.

Rather than relying solely on supplements, individuals struggling with chronic insomnia are encouraged to explore behavioral sleep therapies, relaxation techniques, and better sleep hygiene — strategies that treat the root of the problem without potential long-term harm.

Melatonin may help in the short term, but this new evidence highlights a crucial truth: when it comes to health, even the most natural solutions should be handled with scientific care.