Is Long-Term Melatonin Use Really Safe? What New Research Found About Sleep Supplements and Heart Health

For many people, falling asleep becomes harder with age and lifestyle changes. Stress, hormone shifts, busy evenings, and irregular schedules all affect the body’s natural sleep rhythm. Because of this, melatonin has become one of the most commonly used sleep supplements. It is often seen as natural, gentle, and harmless.

However, new research presented at the American Heart Association’s Scientific Sessions in 2025 suggests that long-term melatonin use may not be as risk-free as once believed.

This article breaks down what the research actually studied, what it found, and what it means in real life.

Sleep, Melatonin and Heart Health

What the Research Studied on the Connection between Sleep, Melatonin and Hearth Health

The research was a large observational study using electronic health records.

Researchers analyzed data from more than 130,000 adults who had been diagnosed with insomnia. Participants were followed for approximately five years. The researchers compared people who used melatonin regularly for at least one year with people who had insomnia but did not use melatonin.

Because this was an observational study, the researchers did not give melatonin to participants. Instead, they looked at existing medical data to identify patterns and associations.

What the Researchers Found - Sleep, Melatonin and Heart Health

The results raised important questions about long-term melatonin use.

Adults who used melatonin for one year or longer had approximately a 90 percent higher risk of developing heart failure over the five-year follow-up period compared with those who did not use melatonin.

Long-term melatonin users were also more likely to be hospitalized for heart failure.

In addition, overall mortality was higher in the group using melatonin long-term, meaning they were more likely to die from any cause during the study period.

These findings suggest that long-term melatonin use may be associated with serious health outcomes, particularly related to heart health.

Does This Mean Melatonin Causes Heart Failure?

No. This is a very important distinction.

The study does not prove that melatonin causes heart failure or death. It shows an association, not a cause-and-effect relationship.

There are several possible explanations for the findings:

People who rely on melatonin long-term often have chronic insomnia, and long-standing sleep problems themselves are linked to higher cardiovascular risk.

Chronic stress, anxiety, depression, and other underlying health conditions may be more common in long-term melatonin users and could contribute to the observed outcomes.

Because melatonin is available over the counter in the United States, not all use may be accurately captured in medical records, which can affect data accuracy.

The researchers themselves emphasized that more studies are needed to determine whether melatonin plays a direct role or whether it is simply a marker for deeper sleep and health issues.

Why This Research Matters

Melatonin is often taken nightly for months or years without much thought, especially because it is marketed as natural and non-addictive. This research reminds us of a few important truths:

• Natural does not always mean harmless.

• Hormones taken regularly from outside the body can interact with the body’s own systems in ways we do not fully understand yet.

• Chronic sleep issues are often a sign of deeper imbalance, not just a lack of melatonin.

Instead of automatically reaching for a supplement, it is important to understand why sleep is disrupted in the first place.

What Experts Currently Recommend

Most experts agree on a balanced approach.

• Short-term melatonin use may still be appropriate for situations like jet lag or brief sleep disruption.

• Long-term nightly use, especially without medical guidance, should be reconsidered in light of this new research.

• Anyone who feels dependent on melatonin to sleep should speak with a healthcare provider to explore underlying causes such as stress, hormone changes, sleep apnea, blood sugar imbalance, or nervous system dysregulation.

Supporting Sleep Without Long-Term Melatonin Use

Rather than relying on melatonin long-term, sleep can often be improved by supporting the body’s natural rhythms:

• Consistent sleep and wake times help regulate the internal clock.

• Morning sunlight exposure helps the brain produce melatonin naturally at night.

• Our eyelids respond to light direction. When light comes from above our head, the brain reads it as daytime, keeping the eyes more open and reducing melatonin production. In the evening, as it gets dark, turning off ceiling lights and using low, warm amber floor lighting helps signal the brain that it is time to wind down and naturally supports melatonin release.

• Reducing artificial light and screen exposure in the evening supports natural hormone signaling.

• Regular cardio physical activity earlier in the day improves sleep quality.

• Calming evening routines and nervous system regulation can make a significant difference.

Bottom Line

Melatonin may still have a place as a short-term tool, but this large study raises valid concerns about long-term, nightly use. Sleep is deeply connected to heart health, hormones, stress, and lifestyle. Instead of masking sleep problems with a supplement, addressing root causes may be safer and more effective for long-term health. If sleep has become a struggle, it may be time to look deeper rather than reaching for another pill.