New Study Links Long-Term Melatonin Use to Increased Heart Failure Risk: What You Need to Know

January 25, 2026

Melatonin, a popular over-the-counter sleep aid, has long been considered safe for short-term use. However, new research published in early 2025 in the Journal of the American College of Cardiology: Advances suggests a potential link between prolonged melatonin supplementation and a modestly elevated risk of heart failure hospitalization in adults over 50. This large observational study provides crucial insights for individuals considering or currently engaged in long-term melatonin use.

Key Findings from the Groundbreaking Study

The research, which analyzed a vast dataset, revealed several important points:

• Study Cohort: Approximately 250,000 adults, with an average age of 58, were monitored for a median period of 7.2 years using US commercial claims data from 2015 to 2022.
• Defining Exposure: Long-term melatonin use was defined as having at least three filled melatonin prescriptions over a minimum of 90 days within any 365-day period.
• Primary Outcome: The study’s main focus was the occurrence of a first heart failure hospitalization.
• Adjusted Risk: Long-term melatonin users showed an adjusted hazard ratio (HR) of 1.14 (95% CI 1.06–1.23) compared to non-users, indicating a 14% higher risk.
• Absolute Risk: While the relative risk was notable, the absolute risk difference remained small, equating to roughly 0.8 additional heart failure events per 1,000 person-years.
• Vulnerable Groups: A stronger correlation was observed in individuals with pre-existing cardiovascular risk factors, such as hypertension, diabetes, or a history of myocardial infarction (heart attack).
• Robust Adjustments: The association persisted even after accounting for various confounding factors, including age, gender, other health conditions, use of different sleep aids, and propensity-score matching.

Important Limitations and Considerations

Both the study authors and editorialists highlighted several critical limitations that are vital for interpreting these findings:

• Observational Design: As an observational study, it can identify associations but cannot definitively prove causation. Other underlying factors might contribute to the observed link.
• Confounding by Indication: Individuals who use melatonin long-term often suffer from chronic insomnia, sleep apnea, engage in shift work, or experience anxiety/depression. These conditions are independently associated with an elevated risk of heart failure, making it difficult to isolate melatonin’s direct effect.
• Dosage Data Gaps: The study lacked precise data on melatonin dosages. While most prescriptions were for 3–10 mg, higher recreational doses, often taken without medical supervision, were not captured.
• Over-the-Counter Use: Data on over-the-counter melatonin purchases were unavailable, likely leading to an underestimation of actual melatonin exposure.
• Sleep Apnea Severity: The study did not adjust for the severity of sleep apnea, a major risk factor for heart failure and a common reason for melatonin use.
• Follow-up Duration: A median follow-up of 7.2 years may be relatively short for a slowly progressing condition like heart failure.
• Unclear Biological Mechanism: The paper did not identify a clear biological mechanism. Authors speculated about potential effects on blood pressure rhythm, inflammation, or autonomic function, but these remain hypothetical.

Other Recent Evidence (2023–2025)

To provide a broader context, it’s helpful to consider other recent research on melatonin’s effects:

• Short-Term Trials: Clinical trials lasting weeks to months have generally shown melatonin to be neutral or slightly beneficial for blood pressure and endothelial function in individuals with hypertension or metabolic syndrome.
• Animal Studies: Animal research has yielded mixed results; some studies indicate melatonin may protect against cardiac remodeling, while others suggest high doses could impair mitochondrial function.
• Lack of RCTs: Crucially, no large-scale randomized controlled trials have specifically investigated the long-term impact of melatonin on heart failure risk.
• European Registries: Several European registries in 2024 reported no clear signal for increased heart failure risk when melatonin was used at typical over-the-counter doses (1–5 mg).

Current Expert Consensus (as of Mid-2025)

Major cardiology and sleep medicine societies, 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 based solely on this single observational study. They generally maintain that melatonin has a favorable safety profile for short- to medium-term use in managing insomnia, jet lag, and certain circadian rhythm disorders, especially when administered at physiologic doses (0.5–5 mg).

However, many cardiologists are now advising additional practical considerations for individuals using melatonin long-term (exceeding 6–12 months):

• Lowest Effective Dose: Utilize the minimum effective dose, as 0.5–3 mg is often sufficient for initiating sleep.
• Prolonged-Release Formulations: If available, prefer prolonged-release formulations that better mimic the body’s natural melatonin rhythm.
• Periodic Reassessment: Regularly evaluate the ongoing need for melatonin; many individuals can gradually reduce or discontinue use after optimizing sleep hygiene practices.
• Symptom Monitoring: Closely monitor blood pressure and any emerging heart failure symptoms, particularly in patients with existing heart failure, reduced ejection fraction, or multiple cardiovascular risk factors.

The Bottom Line for Adults Over 60

For most individuals, occasional or short-term melatonin use (a few weeks to months) at low doses remains one of the safest available sleep aids. However, chronic daily use over several years, especially at higher doses (≥5–10 mg), currently lacks comprehensive long-term safety data and may be associated with a small, increased risk of heart failure, particularly for those already at elevated cardiovascular risk.

If you are using melatonin long-term, it is highly recommended to discuss this with your cardiologist or primary care physician during your next visit. They may suggest a trial reduction in dosage or explore alternative strategies, such as Cognitive Behavioral Therapy for Insomnia (CBT-I), low-dose trazodone, or mirtazapine, if appropriate. Even small adjustments in dose or duration can sometimes make a significant difference in long-term safety and overall cardiac health.

Disclaimer

This article is strictly for informational purposes only and should not be considered medical advice. Never discontinue, initiate, or alter any supplement or medication (including melatonin) without direct consultation with your prescribing physician or cardiologist. Heart failure risk is influenced by a multitude of factors, and melatonin represents only one very small piece of this complex puzzle. Should you experience symptoms such as shortness of breath, leg swelling, persistent fatigue, rapid weight gain, or any other concerning cardiac symptom, seek immediate medical attention. Personalized medical guidance tailored to your specific health profile is absolutely essential.