Chronic Melatonin Use Does Not Increase Heart Failure Risk
Based on current evidence from major cardiovascular guidelines and clinical research, chronic melatonin use does not increase the risk of heart failure and may actually provide cardioprotective benefits. The American Heart Association, American College of Cardiology, and Heart Failure Society of America do not list melatonin as a contraindication or harmful agent in patients with cardiac disease, and these organizations specifically identify harmful medications in heart failure yet melatonin is not included in these warnings 1.
Evidence Supporting Cardiovascular Safety
Guideline-Based Safety Profile
The Society for Perioperative Assessment and Quality Improvement recommends continuing melatonin through the perioperative period, as available evidence demonstrates melatonin is safe in this context 1.
The American Academy of Sleep Medicine guidelines report no serious adverse reactions have been documented in relation to melatonin use across age groups, with the most frequently reported adverse events being headache (0.74%) and dizziness (0.74%) 1.
The American College of Cardiology guidelines address sleep disorders in heart failure patients and imply melatonin's safety by not mentioning it as a harmful agent 1.
Potential Cardioprotective Effects
Recent research actually suggests melatonin may be beneficial for heart failure patients rather than harmful:
A 2025 systematic review and meta-analysis found that melatonin therapy in heart failure patients resulted in significant elevation of quality of life, reduced fatigue and NT-Pro BNP levels, and increased sleep quality and appetite 2.
The same meta-analysis showed trends toward improved ejection fraction and NYHA functional class with melatonin supplementation 2.
Animal studies demonstrate that melatonin reduces cardiac pathology, prevents death of cardiac muscle in response to ischemia-reperfusion, and may prevent cardiac hypertrophy, thereby lessening the development of heart failure 3.
In rat models of isoproterenol-induced heart failure, melatonin reduced mortality, prolonged survival time, decreased oxidative stress, reduced collagen deposition, and attenuated blood pressure decline 4.
Important Safety Considerations
While melatonin does not increase heart failure risk, certain precautions apply:
Warfarin interaction: The American Academy of Sleep Medicine recommends caution in patients taking warfarin due to potential interactions reported to the World Health Organization 1, 5.
Dosing recommendations: Start with 3 mg of immediate-release melatonin, with dose titration in 3 mg increments only if needed, up to a maximum of 15 mg, as higher doses can cause receptor desensitization and more frequent adverse effects 1, 6.
Product quality: Choose United States Pharmacopeial Convention Verified formulations to minimize the risk of contaminants and ensure reliable dosing, as melatonin is regulated as a dietary supplement in the U.S. 1, 5.
Duration of Use Considerations
The American Academy of Sleep Medicine recommends against long-term use of melatonin for chronic insomnia beyond 3-4 months due to insufficient safety data 6.
However, for specific circadian rhythm sleep-wake disorders, melatonin may be used longer-term as these conditions require ongoing chronobiotic therapy 6.
Long-term studies (up to 29 weeks in adults, 24 months in children) show generally favorable safety profiles with no evidence of serious adverse effects, dependency, or tolerance 6.
Common Pitfalls to Avoid
Do not confuse lack of efficacy data for insomnia with cardiac safety concerns: The guideline recommendations against long-term use for insomnia are based on limited efficacy data for that indication, not cardiac safety concerns 6.
Avoid excessive doses: Higher doses (10 mg) may cause receptor desensitization and more frequent adverse effects like morning headache and sleepiness 6.
Monitor for drug interactions: Document concurrent medications before recommending melatonin, particularly warfarin, photosensitizing medications, and antiepileptic drugs 5.