New Study Raises Concerns About Long-Term Melatonin Use

The use of melatonin supplements has become increasingly popular, especially among people with chronic insomnia. However, a new preliminary study presented at the American Heart Association’s Scientific Sessions 2025 in New Orleans suggests that taking melatonin for a year or more may be linked to a higher risk of heart problems. It’s essential to note that the study hasn’t been peer-reviewed, so the findings should be viewed as early evidence, not final answers.

What the Study Found

Researchers analyzed five years of electronic health records from 130,828 adults diagnosed with insomnia. The average age was 55.7 years, and about 61% were women. They compared people who used melatonin long-term (at least 12 months) with similar adults who had insomnia but no record of melatonin use. The main analysis found that adults with chronic insomnia who used melatonin long-term had about a 90% higher chance of developing heart failure over five years compared with adults who didn’t take melatonin.

Understanding Melatonin

Melatonin is a hormone that your body naturally produces to regulate your sleep-wake cycle. Melatonin supplements are widely available in the U.S., with over-the-counter supplements available in doses from 1 to 10 milligrams. However, because melatonin is sold as a dietary supplement, it is not regulated by the FDA, which means the content of the supplement can differ from what is listed on the product label.

The Risks of Melatonin Use

A 2017 study found that the melatonin content of dietary supplements often varies widely from what is listed on the label. Results show that the melatonin content in more than 71% of supplements differed from the label by more than 10%, ranging from 83% less to 478% more than the label stated. Melatonin can be effective for certain circadian rhythm disorders, but there is little to no evidence that it works well as a general sleep aid.

Growing Use and Safety Advisories

Melatonin use has increased in the last two decades across all ages. Following the pandemic, there was a spike in emergency calls related to suspected child melatonin overdoses. In response, the American Academy of Sleep Medicine issued a health advisory urging parents to seek medical guidance before giving melatonin to children or teens. Experts continue to stress caution, especially because supplement content varies so widely and long-term effects remain unclear.

Understanding Insomnia

Chronic insomnia means having trouble sleeping at least three times per week for three months or longer. About 10% of adults experience it. Treatment depends on the cause, but sleep specialists recommend trying healthy sleep habits first for short-term insomnia. For chronic insomnia, however, lifestyle changes often are not enough. The American Academy of Sleep Medicine recommends cognitive behavioral therapy for insomnia (CBT-I) as the first-line treatment for chronic insomnia in adults.

Key Takeaways

This new study found an association between long-term melatonin use and heart risks. It did not show that melatonin causes heart failure. More research is needed before experts can say whether long-term melatonin use affects heart health. Melatonin may seem like a simple fix for trouble sleeping, but it is not risk-free, and it may not help with insomnia in the first place. If you are struggling with chronic sleep problems, talk to a health professional or get help from the sleep team at an accredited sleep center.

Conclusion

In conclusion, while melatonin supplements may seem like a convenient solution for insomnia, the potential risks associated with long-term use cannot be ignored. It’s crucial to approach melatonin use with caution and consult with a healthcare professional before taking it, especially for extended periods. By understanding the potential risks and benefits of melatonin and exploring alternative treatments for insomnia, individuals can make informed decisions about their sleep health.