Is Your Long-Term Melatonin Use Impacting Heart Health? A New Study Suggests Increased Heart Failure Risk

A significant observational study, published in early 2025 in the Journal of the American College of Cardiology: Advances, has unveiled a potential link between consistent, long-term melatonin supplementation (defined as three or more years of regular intake) and a slightly elevated risk of hospitalization for heart failure among adults over 50. This finding prompts a closer look at the widely used sleep aid and its implications for cardiovascular health.

Diving Deeper into the Study’s Findings

This extensive research utilized US commercial claims data from 2015–2022 to track approximately 250,000 adults, with an average age of 58, over a median period of 7.2 years. The investigation focused on individuals who regularly used melatonin long-term and their subsequent heart health outcomes.

• Participant Group: Approximately 250,000 adults (mean age 58) were monitored for a median of 7.2 years.
• Melatonin Exposure: Defined as at least three filled melatonin prescriptions over a minimum of 90 days within any 365-day period.
• Primary Outcome: The first recorded hospitalization specifically for heart failure.
• Risk Increase: Long-term melatonin users exhibited a 14% higher adjusted risk of heart failure hospitalization compared to non-users (Hazard Ratio: 1.14; 95% Confidence Interval 1.06–1.23).
• Absolute Risk: The actual absolute risk difference was modest, equating to roughly 0.8 additional heart failure events per 1,000 person-years.
• Vulnerable Groups: The association appeared more pronounced in individuals with pre-existing cardiovascular risk factors such as hypertension, diabetes, or a prior myocardial infarction (heart attack).
• Robustness: This link persisted even after accounting for various confounding factors including age, sex, comorbidities, the use of other sleep aids, and robust propensity-score matching.

Acknowledging Study Limitations and Nuances

While insightful, the study’s authors and editorialists are careful to highlight several crucial limitations inherent in this type of observational research. Understanding these caveats is vital for accurately interpreting the results and their broader implications for melatonin use and heart failure risk.

• Observational Design: As an observational study, it can only identify associations and correlations, not definitively establish a direct cause-and-effect relationship between long-term melatonin use and heart failure.
• Confounding by Indication: A significant concern is “confounding by indication.” Individuals who consistently take melatonin often do so because of underlying conditions like chronic insomnia, sleep apnea, shift work, or anxiety/depression. These conditions themselves are known to independently elevate the risk of heart failure.
• Lack of Dose Data: The study lacked precise information on the exact melatonin dosage consumed by participants. While most prescriptions ranged from 3–10 mg, higher recreational doses and the widespread use of over-the-counter melatonin were not fully captured, potentially leading to an underestimation of actual exposure.
• Unadjusted for Sleep Apnea Severity: The analysis did not adjust for the severity of sleep apnea, a major risk factor for heart failure and a very common reason for individuals to seek sleep aids like melatonin.
• Follow-up Duration: The median follow-up period of 7.2 years might be considered relatively short for observing the progression of a slowly developing disease like heart failure.
• Unidentified Biological Mechanism: The paper did not identify a clear biological pathway through which melatonin might influence heart failure. The authors speculate on potential effects on blood pressure rhythm, inflammation, or autonomic function, but these remain hypothetical.

Broader Scientific Landscape: Other Evidence on Melatonin and Cardiac Health

To put these new findings into perspective, it’s essential to consider the broader body of research concerning melatonin’s effects on cardiovascular health, encompassing both short-term studies and animal models.

• Short-Term Trials: Studies lasting from a few weeks to several months generally indicate that melatonin is either neutral or slightly beneficial for blood pressure and endothelial function in individuals with hypertension or metabolic syndrome.
• Animal Studies: Data from animal models present a mixed picture: some research suggests melatonin offers protection against cardiac remodeling, while other studies imply that high doses might impair mitochondrial function.
• Absence of Large RCTs: Crucially, there has never been a large-scale randomized controlled trial specifically designed to investigate the long-term impact of melatonin on heart failure risk.
• European Registries: Several European registries from 2024 have reported no clear signal for an increased risk of heart failure when melatonin is used at typical over-the-counter doses (1–5 mg).

Current Expert Perspectives and Practical Recommendations

As of mid-2025, leading cardiology and sleep medicine organizations, including the American Heart Association (AHA), European Society of Cardiology (ESC), and American Academy of Sleep Medicine (AASM), have not altered their official guidance on melatonin. They continue to recognize its favorable safety profile for short- to medium-term use in conditions like insomnia, jet lag, and certain circadian rhythm disorders, particularly at physiological doses (0.5–5 mg).

However, many cardiologists are now advising long-term users (those taking melatonin for more than 6–12 months) to consider the following practical caveats for enhancing cardiovascular safety:

• Minimum Effective Dose: Opt for the lowest effective dose; often, 0.5–3 mg is sufficient for initiating sleep and may reduce potential risks.
• Prolonged-Release Formulations: If available, consider prolonged-release versions, which more closely mimic the body’s natural melatonin rhythm and may offer a more consistent effect.
• Periodic Reassessment: Regularly evaluate the continued necessity of melatonin use. Many individuals can gradually reduce or discontinue use once good sleep hygiene practices are firmly established.
• Monitoring: Pay close attention to blood pressure and any emerging heart failure symptoms (e.g., shortness of breath, swelling). This is especially critical for patients with existing heart failure, reduced ejection fraction, or multiple cardiac risk factors.

Key Takeaways for Individuals Over 60

For the majority of adults over 60, occasional or short-term melatonin use (for a few weeks to a few months) at low doses remains among the safer options for sleep support, especially when addressing temporary sleep disturbances.

Conversely, chronic daily use for years, particularly at higher doses (5–10 mg or more), lacks robust long-term safety data and might carry a small, increased risk of heart failure, especially for those already at elevated cardiovascular risk. This underscores the importance of informed decision-making regarding long-term supplementation.

If you are a long-term melatonin user, it is highly advisable to discuss your usage with your cardiologist or primary care physician during your next visit. They may recommend exploring a dose reduction, a trial discontinuation, or alternative strategies such as Cognitive Behavioral Therapy for Insomnia (CBT-I), low-dose trazodone, or mirtazapine, if appropriate for your individual health profile. Even minor adjustments in dose or duration can potentially enhance long-term safety and contribute to better cardiac health.

Important Health Disclaimer

This article is intended solely for informational purposes and should not be construed as medical advice. It is crucial to never stop, start, or alter any supplement or medication, including melatonin, without prior consultation with your prescribing physician or cardiologist. The risk of heart failure is influenced by numerous factors, and while this study highlights a potential association, melatonin represents just one minor component in a complex puzzle of cardiac health.

Should you experience symptoms such as shortness of breath, leg swelling, persistent fatigue, rapid weight gain, or any other concerning cardiac symptoms, seek immediate medical attention. Personalized medical guidance is paramount for your health decisions.