For most people, melatonin does not raise blood pressure. In fact, it tends to do the opposite. But there is one important exception: if you take a type of blood pressure medication called a calcium channel blocker, melatonin may interfere with it and push your blood pressure up. The answer depends heavily on your specific situation.
How Melatonin Affects Blood Pressure
Your body naturally produces melatonin at night, and this production is tightly linked to your cardiovascular rhythm. Melatonin activates receptors in blood vessel walls that promote relaxation, reduces the “fight or flight” signaling from your nervous system, and increases nitric oxide, a molecule that helps blood vessels widen. The net result is typically a modest drop in blood pressure.
This natural nighttime dip in blood pressure is a normal, healthy pattern. People with high blood pressure often have reduced melatonin production at night, and those whose blood pressure fails to dip during sleep (called “non-dippers”) consistently show lower melatonin levels. So the hormone’s baseline role in the body is blood pressure-lowering, not blood pressure-raising.
What the Clinical Evidence Shows
A meta-analysis of seven randomized controlled trials found that melatonin supplements, on the whole, did not significantly change nighttime blood pressure compared to placebo. But when the researchers separated the data by supplement type, a clear pattern emerged. Controlled-release (extended-release) melatonin lowered systolic blood pressure by about 6 mmHg and diastolic by about 3.5 mmHg during the night. Fast-release melatonin had essentially no effect at all.
The benefit of controlled-release melatonin was most pronounced in the late night and early morning hours, which is when blood pressure naturally starts climbing back up. This makes sense: a slow-release formulation mimics the body’s own gradual melatonin secretion, while a quick burst and fade does not. For people with nighttime high blood pressure, that 6-point systolic drop is clinically meaningful, since nocturnal hypertension carries elevated risk for heart attack and stroke.
The Calcium Channel Blocker Problem
Here’s where melatonin can genuinely raise blood pressure. In a double-blind crossover study, 47 people with mild to moderate high blood pressure controlled by nifedipine (a calcium channel blocker) took either 5 mg of melatonin or a placebo at bedtime for four weeks. During the melatonin phase, their systolic blood pressure rose by an average of 6.5 mmHg and diastolic by 4.9 mmHg across the full 24-hour period. Their heart rate also increased by about 4 beats per minute.
The likely explanation is that melatonin and nifedipine compete with each other. Both interact with calcium channels in blood vessel walls, so taking melatonin appears to partially block the drug’s ability to lower blood pressure. The researchers concluded that melatonin “cannot be considered simply a dietary supplement” for people on this class of medication. If you take amlodipine, nifedipine, diltiazem, or another calcium channel blocker, this interaction is worth discussing with your prescriber before adding melatonin.
Beta Blockers and Melatonin Suppression
Beta blockers create a different but related issue. These medications work partly by blocking the same receptors your brain uses to signal melatonin production. Long-term beta blocker use can cut your natural melatonin synthesis by roughly 50%, which contributes to the insomnia many people experience on these drugs. Lower melatonin levels are also associated with the loss of that healthy nighttime blood pressure dip.
This creates a paradox: the very medication meant to protect your heart may be disrupting the sleep hormone that helps regulate overnight blood pressure. Whether supplementing melatonin in this situation helps restore normal blood pressure patterns remains an open question, with studies producing mixed results. But the connection between beta blockers, poor sleep, and disrupted blood pressure rhythms is well established.
Formulation and Timing Matter
The type of melatonin supplement you take appears to be more important than the dose. Controlled-release formulations consistently outperform fast-release ones for blood pressure effects, likely because they sustain melatonin levels through the night rather than spiking and fading within an hour or two. Most over-the-counter melatonin in the U.S. is fast-release, so people taking it primarily for sleep may not experience any blood pressure change at all, positive or negative.
Timing also plays a role. The studies showing blood pressure benefits used evening dosing, typically 1 to 2 hours before bed, which aligns with the body’s natural melatonin window. Taking melatonin at irregular times or during the day could produce unpredictable effects on blood vessel tone.
Long-Term Use Concerns
Melatonin is widely available over the counter in the U.S. and often treated as harmless, but the American Heart Association has flagged concerns about chronic use. A 2025 scientific statement noted that melatonin is not indicated for the treatment of insomnia in the U.S., and that people should be aware it was not designed for indefinite daily use. The cardiovascular effects of taking melatonin for months or years are not well studied in large populations, which makes long-term safety an open question, particularly for people with existing heart disease or those on blood pressure medications.
For occasional short-term use in people who are not on calcium channel blockers, melatonin is unlikely to raise blood pressure and may modestly lower it. The risk profile changes meaningfully, though, for anyone managing hypertension with medication. In that case, treating melatonin as “just a supplement” can obscure a real drug interaction.