Does Melatonin Cause Heart Disease?
No, melatonin does not cause heart disease—in fact, the available evidence suggests melatonin may have cardioprotective properties and is considered safe for cardiovascular use.
Safety Profile for Cardiovascular Patients
The American Academy of Sleep Medicine reports no serious adverse reactions documented in relation to melatonin use across age groups, with the most common side effects being headache (0.74%) and dizziness (0.74%) 1. The Society for Perioperative Assessment and Quality Improvement recommends continuing melatonin through the perioperative period, demonstrating confidence in its cardiovascular safety 1.
Evidence of Cardiovascular Benefits (Not Harm)
Research consistently demonstrates potential cardiovascular benefits rather than harm:
Patients with cardiovascular disease actually have lower melatonin levels: Individuals with heart failure, hypertension, coronary heart disease, and cardiovascular risk factors typically exhibit lower nighttime melatonin levels, and this deficiency increases the likelihood of adverse cardiac events 2.
Melatonin may reduce blood pressure: Studies show melatonin administration (even at 1 mg doses) can reduce blood pressure to normal range in hypertensive patients, potentially through direct hypothalamic effects, antioxidant mechanisms, decreased catecholamine levels, or smooth muscle relaxation 3.
Cholesterol-lowering effects: Research indicates melatonin suppresses cholesterol formation by 38% and reduces LDL accumulation by 42%, with patients having high LDL-cholesterol showing low melatonin levels 3.
Cardioprotective mechanisms: Melatonin demonstrates anti-inflammatory, antioxidant, and free radical scavenging properties that protect against cardiovascular pathophysiological processes 4, 5.
Important Precautions (Not Contraindications)
While melatonin doesn't cause heart disease, certain precautions apply:
Warfarin interaction: The American Academy of Sleep Medicine recommends caution in patients taking warfarin due to potential interactions 1, 6.
Glucose tolerance: Melatonin has been associated with impaired glucose tolerance in healthy individuals after acute administration, so patients with impaired glucose tolerance should be aware 1, 6.
Optimal Dosing for Safety
Start with 3 mg of immediate-release melatonin, taken 1.5-2 hours before bedtime 1, 7. Higher doses (10 mg) may cause receptor desensitization and more frequent adverse effects like morning headache and sleepiness 7. If ineffective after 1-2 weeks, increase by 3 mg increments up to a maximum of 15 mg 1, 7.
Common Pitfall to Avoid
The major pitfall is assuming melatonin causes cardiovascular harm when the evidence shows the opposite. Patients with cardiovascular disease often have melatonin deficiency, not excess 2. Choose United States Pharmacopeial Convention Verified formulations to ensure reliable dosing and minimize contaminant risk 1, 7.