Melatonin: America’s Favorite Sleep Fix May Have a Hidden Side
Across the United States, millions of adults end their nights with one small pill — melatonin. It’s often described as a “natural sleep aid,” safe enough for anyone struggling with restless nights or late-night screen habits. But new research is raising serious questions about what long-term melatonin use might mean for your heart.
A growing body of evidence, including a 2025 study presented by the American Heart Association, suggests that consistent melatonin use for over a year could be linked to an increased risk of heart failure and other cardiovascular problems. For people who pop it nightly without thinking twice, this finding is enough to make anyone pause.
Melatonin has become part of American bedtime culture — available everywhere from grocery stores to gas stations. But the reality is, while short-term use can help regulate sleep, experts now warn that it may not be as harmless as it appears when used continuously.
What the New Research Reveals About Heart Risk
In a large U.S. database study, researchers followed more than 130,000 adults diagnosed with insomnia. Among those who reported using melatonin for at least a year, the risk of developing heart failure was roughly 90% higher than in those who did not take it regularly.
To put it simply: out of every 100 long-term melatonin users, about five eventually developed heart failure — compared to fewer than three in non-users. Hospitalization rates were also nearly triple in the melatonin group, and deaths from all causes were significantly higher.
These numbers don’t mean melatonin directly causes heart disease — correlation isn’t causation. But the signal is strong enough that cardiologists and sleep specialists are paying attention.
Dr. Michael Reynolds, a cardiologist at Boston Medical Center, explained it this way:
“When you see a supplement tied to higher heart-failure rates, even indirectly, that’s something you can’t ignore. It tells us there’s a deeper connection between sleep health, hormones, and cardiovascular function.”
Why Could Melatonin Affect the Heart?
Melatonin isn’t just a sleep hormone. It’s part of a complex hormonal system that helps regulate blood pressure, oxidative stress, and inflammation — all key factors in heart health.
Here’s what experts suspect may be happening:
- Hormonal imbalance: Long-term supplementation may disrupt the body’s natural production of melatonin, altering circadian rhythms that control blood pressure and heart rate.
- Oxidative stress: Too much external melatonin can interfere with the body’s antioxidant systems, potentially leading to inflammation in blood vessels.
- Sleep dependency: People who rely on melatonin nightly may overlook underlying causes of poor sleep — such as sleep apnea, anxiety, or metabolic problems — which themselves can harm the heart.
In short, melatonin’s role in the heart’s regulatory system may be more complicated than we thought. Over time, this “simple sleep fix” might influence cardiovascular patterns in ways scientists are still uncovering.
America’s Growing Melatonin Habit
Melatonin sales have exploded over the last decade. In 2010, the U.S. market was worth less than $200 million. By 2024, it surpassed $1.5 billion, according to the National Center for Complementary and Integrative Health.
Why the boom?
- The pandemic disrupted sleep for millions.
- Remote work blurred day-night boundaries.
- People sought “natural” alternatives to prescription sleep aids.
- Social media amplified the idea that melatonin is safe because it’s natural.
Unfortunately, most Americans take doses far above what the body naturally produces. A healthy adult’s pineal gland releases about 0.3 milligrams of melatonin nightly, yet supplements often contain 3 to 10 milligrams — sometimes even more.
That’s a ten- to thirty-fold increase over what your body actually needs. Over time, this may desensitize the body’s melatonin receptors, pushing the circadian system off balance.
Expert Opinions: Proceed with Caution
Doctors aren’t saying to throw your melatonin bottle away immediately. What they do recommend is mindful use.
Dr. Laura Becker, a sleep medicine specialist, emphasizes,
“Melatonin should be a short-term solution — a bridge, not a crutch. When people use it long-term, they often delay finding the real cause of their sleep issues.”
Becker adds that many users mistake melatonin for a sedative. It doesn’t “knock you out.” Instead, it adjusts your internal clock to make sleep feel more natural. But when taken excessively or inconsistently, it may do the opposite — confusing the body’s signals rather than calming them.
Cardiologists agree that anyone with heart disease, high blood pressure, diabetes, or obesity should speak with their doctor before taking melatonin regularly. These groups already face elevated cardiovascular risk, and adding a hormone supplement could further complicate things.
How Long-Term Use Might Backfire
The recent findings highlight a crucial misunderstanding about supplements: natural does not always mean risk-free.
Melatonin is a hormone — not a vitamin or herb. Its impact goes beyond sleep. Over time, over-supplementation might:
- Disrupt nighttime blood-pressure regulation.
- Interfere with cardiovascular repair during deep sleep.
- Reduce the body’s natural hormone response.
- Exaggerate fatigue, depression, or irregular heart rhythms in sensitive individuals.
Some case studies have shown that people using melatonin nightly for several years experienced worsened sleep once they stopped — a kind of rebound insomnia that stresses both the nervous system and the heart.
Researchers emphasize that more studies are needed to understand whether melatonin itself is the problem or if long-term users already have underlying conditions that put them at risk. Either way, the takeaway remains: balance and moderation matter.
Understanding the Sleep–Heart Connection
It’s no coincidence that poor sleep and heart disease often show up together. Chronic insomnia raises stress hormones like cortisol and adrenaline — both of which increase blood pressure and heart workload.
In contrast, consistent, high-quality sleep allows the heart to slow down, blood vessels to relax, and the body to perform essential repair work. When melatonin supplements mask a deeper sleep problem, they may prevent this restorative process from happening naturally.
Studies from Harvard and Stanford have repeatedly shown that adults sleeping less than six hours a night have a 20–30% higher risk of heart attack, stroke, and hypertension. Quality sleep is, quite literally, heart protection in disguise.
Safer Sleep Strategies Without Relying on Melatonin
If you’ve been using melatonin for more than a few weeks, it might be time to consider other ways to restore your natural sleep rhythm.
Here are evidence-based, heart-friendly sleep strategies:
1. Maintain a fixed sleep schedule.
Going to bed and waking up at the same time daily trains your body’s circadian rhythm naturally — no pills required.
2. Reduce evening light exposure.
Blue light from phones and laptops suppresses your body’s melatonin production. Try switching off screens at least 60 minutes before bed.
3. Cool your room.
Lowering your bedroom temperature to around 65°F (18°C) supports natural melatonin release and improves deep sleep.
4. Limit caffeine and alcohol.
Both can interfere with deep sleep stages and raise nighttime heart rate.
5. Practice relaxation techniques.
Gentle yoga, meditation, or breathing exercises before bed help activate the parasympathetic nervous system — the body’s “rest and digest” mode — lowering heart strain and improving sleep onset.
6. Address underlying issues.
If you struggle with insomnia or snoring, a sleep study can identify conditions like sleep apnea, which independently increases heart-disease risk.
By focusing on these habits, many people find they no longer need nightly melatonin at all.
The Role of Lifestyle and Heart Health
It’s impossible to talk about sleep without mentioning lifestyle. Nutrition, exercise, stress, and daily routine all play a role in how well the heart and sleep function.
The American Heart Association recommends at least 150 minutes of moderate exercise weekly to maintain heart strength and regulate sleep hormones. Activities like brisk walking, swimming, or cycling not only improve cardiovascular endurance but also make it easier to fall asleep naturally.
A diet rich in magnesium, omega-3 fatty acids, and antioxidants (from foods like salmon, nuts, and leafy greens) also supports both heart and sleep health. On the other hand, heavy late-night meals, sugar spikes, and alcohol can disrupt the body’s circadian balance.
When sleep improves naturally, the need for artificial aids like melatonin often fades away. More importantly, the heart benefits directly — lower blood pressure, improved oxygen flow, and reduced nighttime arrhythmia risk.
What Readers Should Take Away
For many Americans, melatonin has become a nightly ritual — almost as common as brushing teeth. But science is reminding us that even familiar habits deserve a second look.
Melatonin isn’t dangerous in small, short-term doses, but it’s not meant to be a lifelong crutch. If you’ve been using it nightly for months or years, talk to your doctor about tapering off and exploring lifestyle-based alternatives.
Your heart and sleep are deeply connected. Supporting one supports the other. The best long-term strategy for both isn’t found in a pill bottle — it’s built through consistent, healthy daily choices.