Melatonin and your heart share a deeper connection than most people realize. You might take a tablet of melatonin to help you sleep after a long day — but did you know this “natural” hormone might have effects far beyond your bedroom? Recent studies have raised red flags about its long-term impact on heart health, especially in people with sleep disturbances. In this article, we’ll explore what melatonin is, how sleep and heart health are connected, what the latest research shows, and how you can safely get better sleep without putting your heart at risk.
How Melatonin and Your Heart Are Connected: What Science Reveals
Melatonin is a hormone produced by the pineal gland in the brain. It helps regulate the sleep‑wake cycle: levels rise in evening darkness and fall in daylight.
Because of its phase‑shifting and sleep‑promoting effects, melatonin supplements are commonly used for insomnia, jet lag, shift‑work sleep issues, and to help reset the circadian rhythm.
Over‑the‑counter availability in many countries makes it a popular “natural” sleep aid.
But “natural” doesn’t always mean risk‑free—but more on that later.
The Sleep–Heart–Brain Connection
Good, regular sleep is a pillar of healthy brain and nervous‑system function. Poor sleep is linked to impaired cognition, mood problems, and increased neurological stress.
But the connection doesn’t stop there: sleep is also one of the key “Life’s Essentials” for heart health, as emphasised by the American Heart Association (AHA).
Chronic insomnia, sleep apnea, and other sleep disruptions are known independent risk factors for hypertension, heart disease and heart failure.
So when you think of melatonin, it’s not just about sleep—it’s about how sleep quality influences your heart and brain health together.
What the Research Says: Melatonin’s Effects on the Heart
Positive evidence (historical/short‑term)
In several experimental and human studies, melatonin has shown potential cardioprotective effects: anti‐oxidative, anti‑inflammatory, reduction of heart‑muscle damage in ischemia (lack of blood supply) models.
A 2021 meta‑analysis found melatonin administration improved left ventricular ejection fraction (LVEF) in some heart patients and reduced markers of damage (troponin) in humans.
Some reviews and animal studies show melatonin may prevent cardiac hypertrophy and protect endothelial (blood‑vessel) function.
Contrasting new evidence / concern
Very recently (2025) a large observational study (to be presented at the AHA) analysed health‑records of over 130,000 adults with insomnia: those taking melatonin for at least one year had about 90% higher risk of being diagnosed with heart failure over 5 years, and were about 3.5× more likely to be hospitalised for heart failure.
In the analysed data: among melatonin users ~4.6% developed heart failure vs ~2.7% among non‑users in the same insomnia cohort (over 5 years).
Important: the study is observational (not proving causation), and many confounding factors remain (e.g., severity of insomnia, presence of other sleep disorders, underlying heart disease).
Mixed / dosage‐dependent findings
Some older work in hypertensive patients found that evening melatonin actually increased blood pressure and heart rate when combined with certain medications—so caution is needed.
Other reports still support a modest blood‑pressure reduction with melatonin supplementation (2‑5 mg/day for short duration) in some individuals, but effects vary.
What This Means for You: Risks, Safety & Practical Advice
If you have cardiovascular disease or are at risk (hypertension, heart failure, arrhythmia, etc.), you should not assume melatonin is harmless, especially for long‑term nightly use.
The recent large‑scale data suggests a correlation—not proof—that long‑term use may signal or contribute to heart risk.
Short‑term use of melatonin (a few nights, or under medical supervision) still appears relatively safe based on past data—but the long‑term picture is less clear.
Safety tips:
Before starting melatonin, talk to your cardiologist or sleep specialist, especially if you have: known heart disease, arrhythmias, heart failure, uncontrolled hypertension.
If using melatonin: use the lowest effective dose, avoid nightly continuous use unless advised, monitor your heart condition.
Review all other medications and conditions: melatonin may interact with other sleep aids, blood‑pressure meds, and may have different effects when combined with heart‑medications.
Don’t rely solely on supplements: focus first on sleep hygiene, lifestyle changes (see next section).
Healthy Sleep Without Over‑Relying on Melatonin
Because sleep quality directly affects your brain and heart, here are practices you can adopt:
Maintain a consistent sleep schedule: go to bed and wake at the same times each day.
During the day: get bright light exposure (natural daylight) to reinforce your circadian rhythm.
In the evening: avoid screens (blue light), caffeine late, heavy meals close to bedtime.
Create a bedroom environment that’s cool, dark, quiet.
Practice relaxation techniques: deep breathing, progressive muscle relaxation, mindfulness/meditation.
Address underlying sleep disorders: if you snore heavily, wake gasping, have daytime fatigue, consider evaluation for Obstructive Sleep Apnea.
When considering a sleep‑aid (including melatonin), use it as short‑term bridge and with guidance—not as a long‑term crutch.
FAQ (Frequently Asked Questions)
Q1: Can melatonin make heart failure worse?
A: There is no definitive proof that melatonin causes heart failure. But recent data show an association between long‑term melatonin use and higher incidence of heart failure in people with insomnia. More research is needed. ScienceDaily+1
Q2: What is a safe dose of melatonin?
A: Studies often use 1–5 mg doses for short‑term sleep issues. Dosage for long‑term use and in people with heart conditions is not well established—so medical supervision is key.
Q3: Can I take melatonin if I already have heart disease?
A: Possibly—but you must discuss it with your cardiologist or sleep specialist. They will assess your specific heart condition, medications, and risk factors.
Q4: Are there natural alternatives to melatonin?
A: Yes—good sleep hygiene, regular exercise, light‑exposure timing, relaxing pre‑bed routines, and treating underlying issues (anxiety, sleep‑apnea) are all effective. Supplements may help but are not a substitute.
Conclusion
In our quest for better sleep, turning to a “natural” hormone like melatonin seems harmless—but when it comes to your heart and brain, nothing should be assumed risk‑free. The latest research raises important questions about long‑term nightly use of melatonin—especially in people already dealing with insomnia or heart risk. If you find yourself reaching for melatonin every night, take a moment: ask why you’re using it, involve a healthcare professional, and explore lifestyle first. Good sleep supports your brain and heart; let’s make sure the tool you use to sleep better doesn’t cost you in another way.
References / Further Reading:
“Evidence for the Benefits of Melatonin in Cardiovascular Disease” PMC article. PMC
“Long‑term use of melatonin supplements may have negative health effects” AHA newsroom. American Heart Association
“Effects of melatonin on cardiovascular diseases: progress in the past” PMC.