Melatonin has become one of the most widely used sleep supplements in the United States, relied on by millions struggling with insomnia or disrupted sleep. But new research suggests that long-term use of the hormone may come with unexpected risks — including a significantly higher likelihood of heart failure, hospitalization, and early death.

While the findings do not prove that melatonin causes heart problems, experts say the results raise important concerns and highlight the need for medical guidance before using the supplement chronically.

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✅ Key Takeaways

• Long-term melatonin users may have a higher risk of developing heart failure.

• People who used melatonin for a year or more were more likely to be hospitalized for heart failure and more likely to die during the study period.

• Experts emphasize that relying on melatonin long-term may signal underlying heart or metabolic issues.

• The study is observational, not proof of causation, but warrants caution and further research.

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What the Study Found

Researchers analyzed electronic health records from more than 130,000 adults and discovered a striking pattern:

✅ Higher Rates of Heart Failure

• 4.6% of long-term melatonin users developed heart failure
  vs.

• 2.7% of non-users

That means regular melatonin users were nearly twice as likely to develop the condition.

✅ Increased Hospitalizations

Long-term melatonin users were more than three times as likely to be hospitalized for heart failure.

✅ Higher Risk of Death

The risk of dying from any cause during the study period was almost double among chronic melatonin users.

These associations were detected in people who used melatonin consistently for one year or longer — a pattern that raises questions about the supplement’s long-term safety.

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⚠️ Important: Correlation, Not Causation

Despite the concerning numbers, researchers are not claiming that melatonin directly damages the heart.

Instead, they suggest the possibility of a reverse relationship:

➤ The need for regular melatonin may be a signal of underlying heart disease.

Chronic insomnia and sleep disruption are known to:

• elevate blood pressure

• increase stress hormones (like cortisol)

• worsen inflammation

• degrade metabolic health

All of these are established risk factors for heart failure.

In other words, people taking melatonin every night may already be at higher cardiovascular risk — and the supplement may simply be reflecting that.

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Why Experts Are Urging Caution

The study is observational, meaning it shows patterns but cannot confirm cause and effect. It has also not yet undergone formal peer review.

Still, specialists say the findings raise red flags — especially given melatonin’s growing popularity and its unregulated supplement market in the U.S., where purity and dosage can vary widely.

✅ Experts recommend:

• Avoiding long-term use unless medically indicated

• Discussing chronic insomnia with a doctor

• Treating the root cause, not just the symptoms

• Staying cautious with supplements not monitored by the FDA

The study also excluded children and may undercount melatonin use since supplements are not always reported to healthcare systems.

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Melatonin’s Role in the Body — and Why It Matters

Melatonin is a hormone naturally produced by the brain's pineal gland to regulate sleep-wake cycles. Synthetic melatonin is commonly used for:

• occasional insomnia

• jet lag

• shift-work sleep problems

However, it is not meant to be taken indefinitely without medical supervision.

Heart failure, the condition highlighted in the study, occurs when the heart cannot pump enough oxygen-rich blood to meet the body’s needs. Even mild disruptions in sleep quality can worsen cardiovascular strain over time.

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What Should You Do If You Take Melatonin?

✅ Doctors advise:

• Talk to your physician, especially if you've used melatonin nightly for more than 3–6 months

• Review underlying causes of insomnia rather than masking symptoms

• Avoid high doses; many supplements contain far more melatonin than the body naturally makes

• Consider behavioral and lifestyle approaches first, including:

  • consistent bedtime routines

  • reducing caffeine and alcohol

  • limiting screens at night

  • cognitive behavioral therapy for insomnia (CBT-I)

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The Bottom Line

A new observational study suggests that long-term melatonin use may be associated with increased risks of heart failure, hospitalization, and early death. While the findings do not prove melatonin is harmful on its own, they highlight the importance of monitoring chronic sleep issues and discussing ongoing supplement use with a healthcare provider.

As the popularity of melatonin continues to rise, understanding its potential impact on heart health is becoming increasingly urgent.