Melatonin and Heart Failure: What Research Says

Melatonin may help regulate your sleep-wake cycle. A preliminary 2025 AHA study linked long-term melatonin use to a higher risk of heart failure, while other studies have shown mixed findings. Current evidence does not prove that melatonin causes or prevents heart failure. More research is warranted. 

In November 2025, a team of researchers led by Ekenedilichukwu Nnadi, MD, shared their findings at the American Heart Association's (AHA) Scientific Sessions in New Orleans.2 

The study found that taking melatonin supplements for a long time can increase the risk of heart failure, hospitalization due to heart failure, or even death from any cause in people who have chronic insomnia, a condition where people have trouble sleeping. 

Researchers examined the health records of 130,828 adults with insomnia from the TriNetX Global Research Network. They divided them into two groups: 

Both groups were similar in many ways, including age, existing health conditions, medications, lab results, and vital signs. Researchers excluded people with existing heart failure and followed participants for five years. 

Here is what researchers found after five years: 

About 4.6% of melatonin users developed it, compared to 2.7% of those who didn't take it. That's about a 90% higher relative risk (hazard ratio 1.89).2 

That's a big difference, with melatonin users facing a risk that's 3.44 times higher. 

Why were heart failure hospitalizations higher than the diagnosis? 

Hospital records can carry a range of heart-failure-related codes that don't always include the code for a new diagnosis.  This could explain why hospitalizations seemed higher than the number of new heart failure cases found in the study. That makes the hospitalization figure the least reliable of the three measures. 

Researchers also conducted a stricter analysis, requiring at least two melatonin prescriptions separated by 90 days or more. Even then, melatonin use was linked with an 82% higher relative risk of heart failure. 2 

It sounds alarming, but this is a relative figure, not an absolute one. In this study, about 5 out of every 100 melatonin users developed heart failure over five years, compared to about 3 out of every 100 nonusers. 

That's approximately 2 additional cases per 100 people in the melatonin group. The finding is important, but it does not mean melatonin causes those additional cases.2 

Does the Study Prove Melatonin Causes Heart Failure? 

No. The researchers themselves acknowledged that their findings do not establish a cause-and-effect relationship. 

There were several limitations, such as: 

Researchers examined existing health records rather than randomly assigning people to take melatonin or a placebo. Therefore, it is unclear whether the higher heart failure risk was linked to melatonin itself or to other health conditions and lifestyle factors.   

The study was presented at a conference and had not undergone peer review at the time.  

The study did not fully account for melatonin dosage, insomnia severity, and some underlying health conditions. Over-the-counter melatonin use might also have gone unrecorded.  

Some participants may have had untreated sleep apnea, which can disrupt sleep and independently increase cardiovascular risks. 

Early heart failure can cause sleep disturbances. Some people may have started taking melatonin because of sleep problems related to an underlying heart condition. 

What Do Newer Studies Suggest? 

Research published or presented in 2026 suggested a different perspective: 

Danish Nationwide Study:  

This study reported similar five-year heart failure risks among melatonin users and nonusers (approximately 0.56% versus 0.55%), although it suggests there could be a possible association with irregular heart rhythms.3 

U.S. Population Survey Analysis:  

This study found no statistically significant association between recent melatonin use and heart failure after accounting for other factors.4 

SLEEP 2026 study:  

This retrospective analysis suggested that melatonin may not independently increase heart failure risk.5 

Together, these findings suggest that more studies are needed to understand the long-term cardiovascular safety of melatonin, particularly among people with chronic insomnia. 

Can Melatonin Be Good for Your Heart? 

Possibly. Early research suggests melatonin may have heart-protective effects, but evidence remains limited. Larger studies are needed to understand its potential benefits and risks. 

A small study with adults who had heart failure showed that taking melatonin for six months was associated with improvements in: 

However, these findings do not establish melatonin as a treatment for heart failure. 

Can Melatonin Cause Palpitations or Other Heart Issues? 

Evidence linking melatonin to heart palpitations is limited. One 2017 report found extra heartbeats in two individuals, but that's not enough to say for sure that melatonin caused it. 

Palpitations at night may also be linked to conditions such as sleep apnea. Further research is needed to understand whether melatonin affects heart rhythm. 

Is It Safe to Take Melatonin for a Long Period of Time? 

Possibly, melatonin is generally considered safe for short-term use, but its long-term safety is still unclear. According to the National Center for Complementary and Integrative Health (NCCIH), research doesn't confirm whether taking melatonin regularly for months or years is safe. 

This doesn't necessarily mean long-term use is harmful, but more studies are needed to understand its potential risks.  

Common side effects include: 

Melatonin may also interact with certain medications, particularly blood thinners and epilepsy medicines. Pregnant or breastfeeding women, older adults, and people with dementia should be especially cautious and seek medical advice before use. 

If you're choosing a melatonin supplement, check for: 

Remember, melatonin supplements may not always contain the amount listed on the label, so choosing a quality-tested product is important. 

When Should You Talk to a Doctor? 

Talk to your doctor if you take melatonin regularly but still don't sleep well, or if you experience persistent side effects such as daytime drowsiness, headaches, or dizziness. 

Check before increasing your dose or using it long term. If you take melatonin regularly and have a heart problem, you should talk to your doctor before taking it.  

If you snore loudly and feel tired all day, you might have sleep apnea. But if you have a sudden sharp pain in your chest, or difficulty breathing, it might be a sign of a heart attack. Call 911 and seek emergency care. 

Read More: Heart attack symptoms: warning signs,what they feel like & what to do  

How to Sleep Better Without Relying on Melatonin 

Improving sleep doesn't always require supplements. Try adapting to a healthy lifestyle and taking special care of your sleep cycle. 

Beyond healthy sleep habits, researchers are also studying certain nutrients for their potential role in heart health. 

One example is annatto-derived tocotrienols, a form of vitamin E known for its antioxidant properties and potential to support healthy cholesterol levels and blood vessel function. 

Also Read: Tired but Can't Sleep? The Stress and Sleep Connection Explained 

Follow the tips below to improve your sleep:

Conclusion 

The connection between melatonin and heart failure is still being studied. While a preliminary 2025 study raised concerns about long-term melatonin use, newer research has shown mixed findings. More studies are needed to understand its long-term effects on heart health.  

Melatonin is still a reliable option for getting your sleep cycle back on track for a short time. But if you rely on it for months or years, or have existing cardiovascular conditions, consult your doctor to make sure you're supporting both your sleep and your heart. 

FAQs 

Q1. Can I take melatonin if I have heart disease? 

No, it is best to avoid taking melatonin without consulting your cardiologist. Although some small studies suggest melatonin may have benefits, its long-term safety is still unclear. Consult your doctor to determine whether melatonin is suitable for you based on your heart condition and current medications.  

Q2. Who should avoid melatonin? 

Avoid melatonin without medical advice if you have heart problems, high blood pressure, or an autoimmune condition, or if you take blood thinners, diabetes medications, or sedatives. Pregnant and breastfeeding women should also avoid it unless advised by their doctor. 

Q3. What are the side effects of taking melatonin every night? 

Taking melatonin every night may cause headaches, dizziness, nausea, and daytime drowsiness. While it is generally considered safe for short-term use, its long-term effects, including potential risks to heart health, are still being studied. 

Q4. How to improve sleep with heart failure? 

If you have heart failure or heart disease, it is important to maintain a consistent sleep schedule, try to keep your bedroom cool and quiet, and avoid taking caffeine before bedtime, as it may help improve sleep. However, if you experience breathlessness at night or frequent sleep disturbances, consult your doctor to rule out any other underlying cause. 

Q5. Do Heart Failure Patients Sleep a Lot? 

Yes, some people with heart failure may feel unusually tired and sleep more due to fatigue and reduced energy levels. However, others may struggle to sleep because of breathlessness, fluid buildup, or sleep apnea. 

References