For decades, melatonin has been marketed as a gentle, natural solution for sleepless nights. Sold in pastel bottles and sweetened into gummies, it promised to coax us back into harmony with our body’s rhythms. Millions have come to rely on it nightly, believing that if it was “natural,” it must also be safe. But new research is calling that assumption into question.

At the 2025 American Heart Association’s Scientific Sessions in New Orleans, scientists presented a startling finding: people who take melatonin for more than a year may face a 90 percent higher risk of heart failure. The data came from one of the largest analyses ever conducted on melatonin use, based on the health records of over 130,000 adults with chronic insomnia.

At first glance, the conclusion seems almost contradictory. Melatonin is the hormone that signals the onset of night, the molecular whisper that tells our cells it’s time to rest and restore. It has been celebrated for its antioxidant properties and its ability to synchronize the body’s internal clock. How could something so closely tied to sleep and repair be connected with one of the most serious cardiovascular outcomes known to medicine?

This question lies at the heart of the debate now unfolding in both scientific and spiritual circles. What if the problem is not melatonin itself, but what our use of it reveals about our relationship with sleep, nature, and the rhythms that govern life?

What the New Study Found

The new study, led by Dr. Ekenedilichukwu Nnadi of SUNY Downstate/Kings County Primary Care in Brooklyn, used the TriNetX Global Research Network, a database containing millions of anonymized medical records from around the world. Researchers identified over 130,000 adults diagnosed with chronic insomnia, averaging 55 years of age, and divided them into two groups: those who had used melatonin for at least a year and those who had not used it at all.

Over a five-year follow-up period, the differences were striking. Long-term melatonin users were nearly twice as likely to die from any cause, over three times as likely to be hospitalized for heart failure, and had about a 90 percent higher chance of developing the condition in the first place.

The researchers carefully emphasized that their work did not prove causation. Observational studies can reveal correlations, but they cannot establish what causes what. Still, even after matching participants on forty variables, including age, gender, race, blood pressure, and medical history, the association between long-term melatonin use and heart failure remained.

The study’s authors pointed out that many melatonin products sold in the United States are poorly regulated. Because melatonin is considered a dietary supplement rather than a drug, manufacturers can sell it without standardized dosage or purity requirements. In some cases, the amount of melatonin in a pill may vary dramatically from what the label claims.

This variability means that people may be taking far higher doses than their bodies need. The pineal gland naturally produces melatonin in quantities measured in micrograms—less than one-tenth of a milligram per day. In contrast, common supplements contain between 3 and 10 milligrams, hundreds of times more than what the body would ever produce naturally.

As Dr. Nnadi explained, “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.”

Melatonin: Nature’s Nighttime Signal

To understand how melatonin could be linked to heart health, we first need to revisit its biological role. Melatonin is secreted by the pineal gland, a small, pinecone-shaped structure deep in the brain. Its production is triggered by darkness and suppressed by light. This daily rhythm helps coordinate the body’s internal clock, known as the circadian rhythm.

At night, melatonin levels rise, signaling to every cell that it’s time for rest, repair, and regeneration. This rhythm affects everything from blood pressure and body temperature to metabolism and immune function. During sleep, the cardiovascular system slows, blood pressure drops, and the heart gets a chance to rest from its daily exertion.

When we flood the body with external melatonin, especially in large or mistimed doses, we may unintentionally override this natural timing system. The body’s delicate hormonal dance depends not just on the presence of certain molecules but on their timing, duration, and intensity.

Short-term use of melatonin—such as for jet lag or short bouts of insomnia—appears to be safe for most people. But the long-term effects, particularly at high doses, are less understood. Studies in animals have shown that chronically high melatonin levels can alter cardiovascular function, hormone balance, and inflammation patterns.

This does not mean melatonin is inherently dangerous. Like all hormones, it is powerful, and power in biology always demands respect.

When “Natural” Doesn’t Mean Harmless

One of the reasons melatonin became so popular is its image as a “natural” alternative to prescription sleeping pills. Yet natural does not always mean safe. Arsenic is natural. So is hemlock. The assumption that natural substances cannot harm us is one of the oldest and most persistent misconceptions in modern wellness culture.

Unlike most prescription drugs, melatonin supplements are not regulated by the Food and Drug Administration in the same way pharmaceuticals are. Independent tests have found some melatonin products to contain anywhere from one-half to four times the amount listed on their labels. Others have been found to include serotonin and other contaminants that could influence mood and cardiovascular function.

Dr. Wendy Troxel, a behavioral sleep medicine specialist at the RAND Corporation, has warned that “the availability of 5mg and 10mg doses defies logic.” The body’s natural rhythm depends on a gentle rise and fall of melatonin levels through the night. Oversaturating those receptors with massive doses may interfere with the body’s ability to regulate other hormones, including those that affect the heart and blood vessels.

Melatonin also interacts with other biological systems, including insulin regulation, oxidative stress, and immune response. Too much of it, or taking it at the wrong time, could disrupt these finely tuned systems, particularly in older adults or people with underlying health conditions.

It’s not that melatonin itself is toxic—it’s that we may be using it in ways our bodies were never designed to handle.

The Heart’s Connection to Sleep

Cardiologists have long known that poor sleep is one of the strongest predictors of cardiovascular disease. The American Heart Association even lists sleep as one of its “Essential 8” lifestyle factors for heart health, alongside diet, exercise, and cholesterol control.

During sleep, the body lowers blood pressure, reduces inflammation, and regulates hormones that control blood sugar and fat metabolism. Chronic insomnia interrupts these processes. Over time, it contributes to hypertension, obesity, diabetes, and eventually heart failure.

A separate study published in Frontiers earlier this year found that people who consistently go to bed after midnight face a significantly higher risk of heart attack. The researchers concluded that sleep timing itself—when we go to bed—may be as important as sleep duration. Late nights disrupt the body’s circadian rhythm, which governs not only sleep but also cardiovascular repair.

Melatonin lies at the center of that rhythm. It signals the heart and blood vessels that night has arrived and that it’s time to relax. But if we use synthetic melatonin at irregular hours or in unnatural amounts, we may distort this communication. The heart, like the brain, depends on rhythm. Each beat is part of a cosmic pulse, synchronized to cycles of light and darkness.

Some researchers suggest that excessive melatonin could desynchronize this system. Each cell in the heart contains its own molecular clock, and if the brain’s signals no longer match the cellular rhythm, the result could be subtle stress, inflammation, or metabolic strain.

Insomnia as a Mirror of Modern Life

While the study has raised alarms about melatonin’s safety, it also sheds light on a larger cultural problem. Chronic insomnia is not just a medical condition; it’s a symptom of a society out of balance.

We live in a world that never turns off. Artificial light extends the day far beyond sunset. Screens fill our eyes with blue light that tricks the brain into thinking it’s still noon. The result is a global epidemic of sleeplessness, with nearly one in three adults not getting the recommended seven hours of sleep per night.

Melatonin supplementation has become our chemical shortcut to counteract this disconnection from natural cycles. Instead of recalibrating our relationship with darkness, we reach for a pill to simulate what our bodies once did automatically.

The irony is that our dependence on melatonin may reflect not only a biological imbalance but also a spiritual one. In ancient traditions, the pineal gland—the organ that produces melatonin—was considered a bridge between physical and spiritual awareness. It was seen as the “seat of the soul,” a portal between waking consciousness and the dream world.

Sleep was not merely rest; it was a form of return, a nightly re-immersion into the unseen layers of existence. When we lose this rhythm, we lose something sacred: the surrender that allows both body and spirit to renew themselves.

Our sleeplessness, then, is more than a medical issue. It is a crisis of rhythm. And the rising concern over melatonin may be urging us to restore the balance between stimulation and stillness.

The Science of Reconnecting With Rest

If melatonin supplements are not the long-term answer, what is? The good news is that science offers a variety of natural methods to improve sleep without pharmacological intervention.

Daytime exposure to bright light helps reinforce the body’s circadian rhythm, signaling to the brain when to produce and when to suppress melatonin. Avoiding screens and bright lights in the evening allows melatonin to rise naturally. Maintaining a consistent bedtime and wake time anchors the body’s internal clock.

Simple lifestyle choices also matter. Limiting caffeine and alcohol, eating earlier in the evening, and exercising during the day all contribute to better sleep quality.

Behavioral therapies, particularly cognitive behavioral therapy for insomnia (CBT-I), have shown strong and lasting results. CBT-I works by reshaping habits and thoughts around sleep, training the body to trust its own timing again.

These methods are not quick fixes, but they are deeply restorative. They teach the body to remember what it already knows—to follow the ancient rhythm of light and darkness, action and rest.

Sleep hygiene may sound clinical, but at its heart, it is a practice of self-alignment. When we treat sleep as a sacred ritual rather than a nightly inconvenience, we begin to experience it as it was meant to be: a reunion with our own natural intelligence.

Between Science and Spirit

The melatonin story sits at the crossroads of science and spirituality. On one hand, it is a clear call for more rigorous research and better regulation of supplements. On the other, it is a symbolic reminder that even in our search for rest, we tend to seek control rather than surrender.

Melatonin, when used properly, can be helpful—especially for temporary rhythm disruptions like jet lag or shift work. But when used nightly for years, it may become a way of masking deeper imbalances instead of healing them.

Perhaps the real message of the American Heart Association’s study is not to fear melatonin but to listen to what it’s telling us. The human body already contains the machinery for perfect sleep. It is guided by light, temperature, and the quiet intelligence of the pineal gland. When those cues are disrupted, instead of forcing the body into compliance, we can learn to restore the conditions it needs to find its own rhythm again.

The heart and the pineal gland are both rhythmic organs—one beats, the other pulses with light. Each mirrors the other in its devotion to pattern. When our external habits fall out of sync with these inner rhythms, we experience not only fatigue but disconnection from the world around us.

Sleep, in this light, becomes a metaphor for trust. It is the act of letting go, of allowing the universe to hold us for a few hours while the body repairs itself. No pill can replicate that kind of surrender.

Returning to the Natural Rhythm

The discovery that long-term melatonin use may raise the risk of heart failure does not mean that the hormone is inherently dangerous. It means we are being invited to approach it with more awareness and restraint.

Our biology is a symphony of cycles: circadian, hormonal, seasonal. When we try to engineer these cycles through artificial means, we may find short-term relief but long-term imbalance. The body’s wisdom lies in rhythm, not in resistance.

Science is catching up to what ancient traditions have long taught: that health is not a static state but a dynamic dance between activity and rest, light and dark, giving and receiving. The more we honor that dance, the less we need to manipulate it.

Melatonin, the so-called sleep hormone, has become a mirror for our modern condition—a society desperate for rest, reaching for shortcuts instead of alignment. The real medicine is simpler and older: respect the night, dim the lights, slow the mind, and listen for the quiet pulse of the heart.

In that quiet, healing begins—not from a bottle, but from the timeless intelligence that beats within us all.

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