Is melatonin good for heart health? Depends who you are.
Some studies point to melatonin use as beneficial to heart health, while others say the opposite. Here’s how to make sense of the complex research.
Along with being a hormone naturally produced in the brain, melatonin is one of the most widely used sleep supplements in the United States, with millions of people taking it in hopes of a better night's rest.
The supplement is often marketed to consumers as a gentle, “natural” remedy that is widely perceived as benign. Yet the science surrounding its effects beyond sleep—particularly on the heart—is far more complex and unsettled than many consumers realize.
“Melatonin has been praised for its accessibility, presumed safety profile, and innocuous effects on sleep, but research continues to struggle with understanding the complexities revolving around this seemingly simple supplement,” says Doris Chan, a practicing cardiologist at NYU Langone Hospital.
Indeed, a growing body of research suggests that melatonin’s effects on the heart are nuanced and sometimes even contradictory.
Some studies point to modest benefits, such as reductions in nighttime blood pressure or improvements in certain measures of cardiac function. Other research raises concerns, including increases in blood pressure in otherwise healthy adults, episodes of very slow heart rate, and higher risks of heart failure. And some studies find little to no measurable cardiovascular effect at all.
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With evidence pointing in so many different directions, scientists are working to better understand all the ways melatonin interacts with the cardiovascular system—and how people might use the supplement more safely.
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The mechanisms behind how melatonin impacts the heart
When produced naturally, melatonin is secreted primarily by the pineal gland in the brain and is best known for regulating circadian rhythm. But its influence can extend beyond sleep, particularly when taken as a supplement.
That's because melatonin exerts its effects by binding to two primary receptors, MT₁ and MT₂. While these receptors are concentrated in the brain’s circadian centers, they are also found throughout cardiovascular tissues, including in blood vessels and heart muscle. When activated, they can influence vascular tone, heart rate, and autonomic nervous system signaling.
At the cellular level, this means melatonin “acts as a signaling molecule with direct and indirect effects on the cardiovascular system,” says Shaline Rao, a cardiologist at NYU Langone Hospital.
But these responses are far from uniform since dose, timing of intake, formulation, the use of other medications or supplements, and underlying health can all influence how melatonin behaves in the cardiovascular system.
How melatonin impacts blood pressure
Although blood pressure is the most extensively studied cardiovascular outcome in melatonin research, the findings remain mixed.
Some small studies and a subsequent meta-analysis suggest that controlled-release melatonin could modestly reduce nocturnal blood pressure in people with hypertension, potentially through a combination of improved sleep quality and direct vascular effects. Other research also shows blood pressure improvements for people with type 2 diabetes and hypertension.
But the supplement's effects are not one directional. “Melatonin acts on two receptors: one that lowers blood pressure, with the other potentially causing an increase in blood pressure,” says Rao. "In a healthy adult, these changes are modest and may not be notable," she says, but the effects may be more pronounced in people with underlying cardiovascular conditions or those taking other medications or supplements.
The studied heart-health benefits of taking melatonin
Despite these uncertainties, some research suggests melatonin may offer cardioprotective effects under specific conditions, largely due to its antioxidant and anti-inflammatory properties.
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Preclinical studies, for example, indicate that melatonin can reduce cardiac injury following a heart attack or stroke. Other studies suggest melatonin may reduce the risk of cardiac injury during cardiac surgery, lower markers of oxidative stress, and improve certain measures of cardiac function, says Rao. One study shows the supplement could even be used as a novel treatment for improving symptoms in heart failure patients.
Still, the clinical significance of these findings remains unclear. In a 2022 systematic review, for example, “there appeared to be no consistent benefit on blood pressure, coronary artery disease, or cardiac function,” says Clyde Yancy, former president of the American Heart Association and the current chief of cardiology at Northwestern University Feinberg School of Medicine.
While he acknowledges melatonin’s possible benefits related to oxidative stress reduction, Yancy cautions that “this remains a theoretical consideration until there is more—much more—clinical science to drive both indication (where it works) and use (how it works).”
The cardiovascular downsides of taking melatonin
At the same time, a growing number of studies raise concerns about possible cardiovascular risks associated with melatonin use, particularly with long-term supplementation or among certain populations.
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Perhaps the most striking findings come from a large observational analysis presented at the 2025 American Heart Association Scientific Sessions. The analysis showed that, among adults with insomnia, those who reported using melatonin for at least 12 months had a higher incidence of heart failure over five years compared with matched non-users. In fact, “the users who took melatonin for a year or longer had about a 90 percent higher risk of developing new-onset heart failure over five years versus matched non-users,” says Rao.
But because the research was observational, "it does not prove causation," Rao stresses. The associations may instead reflect underlying conditions—such as chronic sleep disorders, obesity, or other comorbidities—that both prompt melatonin use and increase cardiovascular risk. Even so, Rao says, “the magnitude of the association is large enough to raise red flags,” particularly for people with existing cardiovascular risk.
There is also evidence that melatonin may interfere with certain cardiovascular medications, including calcium-channel blockers, potentially blunting their blood pressure-lowering effects.
Such effects are among the reasons some clinicians avoid recommending melatonin altogether. “Melatonin is not a supplement that I recommend or prescribe because of the observational studies showing an association with heart failure,” says Eleanor Levin, a clinical professor of medicine at Stanford University School of Medicine.
Despite understanding such caution, “the totality of data doesn’t support harm caused by melatonin—especially at physiological or low doses," Yancy says.
Where the science still needs to go—and what to do in the meantime
Taken together, the evidence paints a picture that is neither wholly reassuring nor definitively alarming. Instead, it reflects a field still grappling with the biological complexity of the supplement and significant gaps in long-term data.
To clarify melatonin’s long-term cardiovascular safety, scientists need “more robust research,” says Chan, including large randomized controlled trials that use standardized doses and formulations, follow participants over extended periods, and account for underlying health conditions and medication use. Distinguishing between pharmaceutical-grade melatonin used in research and the highly variable over-the-counter products available to consumers is also critical.
Despite the complexities surrounding melatonin, the supplement is generally considered safe for short-term use and may be appropriate for some individuals under medical guidance. “Shift workers, people who frequently experience jet lag, and those with delayed sleep–wake phase disorder may all benefit from regulation of their circadian rhythm with melatonin,” Rao says.
Still, caution is warranted for some—particularly for people with existing heart disease or those taking multiple cardiovascular medications. Anyone with other health conditions “should consult their physician before starting melatonin,” Rao advises.
She also recommends starting with the lowest effective dose, taking it about 30 to 90 minutes before sleep, and avoiding long-term nightly use. “The duration of therapy should be limited to less than three months,” echoes Yancy. Rao further advises choosing products independently tested by reputable third parties while also monitoring blood pressure and heart rate.
Experts also emphasize that proven strategies such as regular physical activity, a heart-healthy diet, and adequate sleep remain foundational to cardiovascular health.
“Let’s not rush to impugn a therapy that may help with sleep—especially since 20 percent or more of adults experience sleep challenges,” says Yancy. “But let’s also not hesitate to pursue all potential options to reduce heart disease risk and treat established conditions.”
