The quest for sleep: New research questions the safety of common aids

• A new study links long-term melatonin use (one year or more) to a significantly higher risk of heart failure and death in adults with insomnia.
• Researchers found a 90% higher risk of heart failure diagnosis and nearly double the risk of death from any cause over five years in melatonin users.
• Experts caution the study cannot prove cause and effect, and factors like insomnia severity or other health conditions may influence the results.
• A separate sleep lab study found that all-night pink noise, a popular sleep aid, reduces crucial REM sleep by about 15-20 minutes per night.
• Both findings challenge common assumptions about the safety and efficacy of popular over-the-counter sleep aids.

For millions struggling with insomnia, the promise of a safe, natural solution has long been found in a bottle of melatonin or the gentle hum of a sound machine. However, emerging research presented at major scientific conferences is casting a shadow of doubt over these popular remedies, suggesting that their long-term or nightly use may carry unintended health consequences. Two separate studies—one on the hormonal supplement melatonin and another on the acoustic aid pink noise—are prompting experts to urge caution, highlighting significant gaps in our understanding of the long-term safety and efficacy of widely marketed sleep solutions.

Melatonin’s murky heart risks

At the American Heart Association’s Scientific Sessions 2025 in New Orleans, researchers presented a startling analysis that challenges melatonin’s benign reputation. The study, which reviewed five years of electronic health records for over 130,000 adults with chronic insomnia, compared those who used melatonin for at least one year with those who never used it. The findings were significant: long-term melatonin users had a 90% higher risk of developing heart failure, were 3.5 times more likely to be hospitalized for it, and were nearly twice as likely to die from any cause over the study period compared to non-users.

The research, while compelling, comes with important caveats. Experts were quick to note that the observational study design cannot prove a direct cause-and-effect relationship. Factors such as the underlying severity of insomnia, co-existing mental health conditions, or the use of other medications could be influencing both the decision to use melatonin long-term and the increased health risks. Furthermore, in countries like the U.S. where melatonin is an unregulated over-the-counter supplement, usage documented in formal health records is likely incomplete. The study’s lead author, Dr. Ekenedilichukwu Nnadi, emphasized that the association “raises safety concerns about the widely used supplement” and warrants further investigation.

This historical context is crucial. Melatonin transitioned from a prescription hormone to a widely available dietary supplement in the U.S. in the 1990s, leading to a boom in its use as a “natural” sleep aid. Its regulatory status means potency and purity can vary between brands, and long-term safety data has lagged far behind its popularity. The new findings suggest that for chronic insomnia—a condition for which melatonin is not formally indicated as a treatment in the U.S.—indefinite use may not be as harmless as once assumed.

The unexpected cost of a soothing sound

Parallel concerns are emerging from the world of acoustic sleep aids. A rigorous sleep-laboratory study from the University of Pennsylvania, published in the journal Sleep, investigated the effects of pink noise, a sound often marketed as a gentler, more brain-friendly alternative to white noise for masking disturbances. The seven-night study with 25 healthy adults yielded counterintuitive results: playing pink noise continuously at a moderate volume (about 50 decibels) reduced rapid eye movement (REM) sleep by an average of 15 to 20 minutes per night.

REM sleep is a critical phase for emotional processing, memory consolidation and brain restoration. The study found that pink noise both prevented the initiation and disrupted the maintenance of this vital stage. When pink noise was used to mask actual environmental noise—simulating real-world use—the negative effects compounded, leading to reductions in both deep sleep and REM sleep. “The combination kind of wreaked havoc on the sleep,” noted lead author Dr. Mathias Basner.

In a telling contrast, simple foam earplugs were highly effective at mitigating the impact of environmental noise, recovering most of the lost deep sleep without harming REM sleep. The study did not find immediate next-day cognitive deficits from a single night of pink noise use, but participants consistently reported worse subjective sleep quality, alertness and mood. Dr. Basner pointed out that the cumulative effect of losing 20 minutes of REM sleep nightly, especially for those already sleep-deprived, could have long-term implications for emotional and brain health.

Navigating a multibillion-dollar sleep industry

These studies arrive amid a global sleep aid industry valued in the tens of billions of dollars, fueled by pervasive insomnia and aggressive marketing of products often billed as “scientifically backed” or “natural.” The new research underscores a persistent problem: a significant lack of rigorous, long-term safety and efficacy data for many consumer sleep solutions. For melatonin, the question is one of cardiovascular safety over years of use. For sound machines, it’s about understanding the neurophysiological impact of broadcasting constant, artificial noise into the sleeping brain night after night.

Particularly vulnerable populations, such as infants and children, raise additional red flags. Newborns spend roughly half their sleep in REM, a stage crucial for brain development. The widespread use of white or pink noise machines in nurseries, while practical for masking household sounds, may now require a more cautious, evidence-based approach in light of findings that broadband noise reduces REM sleep.

A call for informed caution

The converging messages from these studies are not necessarily to abandon all sleep aids, but to eREM Rmploy them more mindfully and with managed expectations. For patients and physicians considering melatonin, the research suggests it should likely be viewed as a short-term option for circadian rhythm adjustment, not a perpetual cure for chronic insomnia, amelatonnd its long-term use should be approached with caution until more definitive safety data is available.

For those seeking acoustic relief from noise pollution, the evidence currently suggests that blocking sound (with earplugs or better bedroom insulation) is physiologically superior to masking it with more sound. If sound machines are used, experts recommend keeping the volume as low as possible, placing the device far from the bed, and considering using a timer to turn it off after sleep onset rather than playing it all night.

Rethinking the path to restorative sleep

Ultimately, this new research reinforces a fundamental principle: sleep is an active, complex neurological state that can be subtly disrupted by internal and external interventions. The quest for simple, over-the-counter solutions to complex sleep problems may sometimes lead to unforeseen trade-offs. As both studies conclude, more research is urgently needed. In the meantime, these findings serve as a critical reminder for consumers, clinicians and regulators to scrutinize popular health trends with a skeptical eye and prioritize rigorous science over marketing claims. In the delicate ecosystem of sleep, the most “natural” aid may often be the hardest to package and sell: a dark, quiet and cool room, reserved for rest and nothing else.

Sources for this article include:

TheEpochTimes.com

Academicoup.com

Heart.org