Melatonin and Blood Pressure

People usually associate melatonin with sleep aids – and it is a natural one… But among it’s other great attributes, melatonin also can help lower elevated blood pressure.

To learn more about it, I interviewed Russel Reiter, Ph.D., a researcher at the University of Texas–San Antonio’s Department of Cellular and Structural Biology who knows more about melatonin than practically anybody on the planet. He’s conducted numerous studies on melatonin and written hundreds of scientific papers. Every one of those studies indicates that having a robust melatonin level is associated with better health. Because of his expertise I contacted him to ask about the connection between melatonin and blood pressure.

One of the things I learned from him is that the commercialization of electricity has had a damaging effect on our collective melatonin level. Among other things, electricity allows us stay up later than nature intended, which throws off our natural response to sunlight and darkness. And that means our bodies produce less of this important hormone.

The pineal gland − located behind the forehead − is stimulated to produce melatonin only in darkness. Therefore, Dr. Reiter believes our ongoing exposure to artificial light has caused us to become relatively deficient in melatonin. In turn, this has had adverse effects on the body’s ability to regulate sleep and other biological rhythms. Yet another result of our deficiency may be a tendency toward elevated blood pressure.

How to Lower Your Blood Pressure with Melatonin

Blood pressure naturally fluctuates over a 24-hour period, and is highest during the day and lowest at night. Researchers call this natural drop in pressure a nocturnal dip. Some people dip only slightly or not at all, while others dip as much as 20–30 percent from their daytime highs. The folks in the 20–30 percent range are called “extreme dippers.”  Others, just called “dippers,” experience drops of 10–20 percent.

These labels may sound a bit odd, but they’re important. Both extreme dippers and dippers have a much lower rate of death from cardiovascular events. What’s more, melatonin can help you become one of them.

Ongoing research has shown that oral melatonin supplements can promote the dipping process. They can reduce nocturnal systolic blood pressure by about 6 mm/Hg, and diastolic pressure by 4 mm/Hg. Not surprisingly, the studies also indicate that melatonin improves sleep quality, which allows the body to relax more. But they also show that melatonin is involved in biochemical reactions that influence blood pressure levels. This effect has been observed both in people with high blood pressure as well as those with normal blood pressure.

When I was in medical school, more than 40 years ago, 80–90 percent of high blood pressure was of uncertain causation. Only about 10 percent was linked to known conditions, for example, an overactive thyroid, a congenital narrowing of the aorta, or an adrenal tumor. The bulk of the problem − that of unknown cause − was named essential hypertension.

In recent years, however, we’ve learned that high blood pressure is due primarily to oxidative stress. In other words, the body’s antioxidant systems become overwhelmed, leading to excess oxidation, endothelial dysfunction, and eventually constriction of blood vessels. We’ve also learned that melatonin plays a number of special protective roles in the blood. It helps relax the sensitive and critical lining of your blood vessels – called the endothelium. That’s very important. Relaxed vessels are more flexible and responsive.

Melatonin is also a potent antioxidant, and able to help counteract free radicals that cause oxidation. Finally, it may influence the expression of genes deep within the brain that regulate blood pressure.

So, as Dr. Reiter explained to me, anything that compromises melatonin production could also cause a rise in blood pressure. It conceivably could even convert dippers into non-dippers.

Drugs, Sunlight and Low Melatonin

In Dr. Reiter’s view, the top threats to adequate melatonin production are our level of exposure to bright lights after darkness, and our habit of sleeping only 5–6 hours a night. The aging process also has an impact (melatonin production drops over time), as does the use of drugs like beta blockers and tranquilizers (both inhibit our ability to make the hormone). Together, these things suggest that it’s a good idea to supplement with melatonin as we get older.

The point about beta blockers is an interesting one given that they’re widely prescribed to lower blood pressure − yet it would seem that their effect on melatonin production may actually cause an increase in blood pressure. I’ve always considered beta blockers to be among the safest cardiovascular medications available, and an essential therapy for patients who’ve had a heart attack. But their impact on melatonin production is a wise reminder that even good drugs have side effects. Beta blockers can also cause nightmares and insomnia!

If you’re taking a beta blocker for any reason, you need to take a melatonin supplement. Moreover, take your medication in the morning, not before bed as many doctors recommend, when it is most likely to interfere with your natural tendency to produce melatonin.

Best Form of Melatonin

When it comes to melatonin supplements, Dr. Reiter prefers the sublingual form. “The advantage of taking melatonin under the tongue is that the first pass through the liver is delayed,” he said.

Whenever you swallow a tablet or capsule, it has to go through the digestive process and then be processed by the liver before it enters the body’s general circulation. Not only is this process long, but it’s likely that some of the substance in the pill or capsule will be lost.

“The sublingual tablets dissolve in roughly 15 minutes, and shortly thereafter most of the melatonin is probably absorbed,” Dr. Reiter said. “You get more bang for your buck this way.” For the past 17 years, he’s been taking three 5 mg tablets at before bedtime.

Because most products have from 1 to 3 mg or less, you may think 15 mg is a lot. But as Dr. Reiter pointed out, “the commercial] dosages are not based on anything scientific. I think they are too low. We don’t take sufficient amounts of melatonin, but the problem is that nobody knows the optimum amount.”

Is Melatonin Safe?

Melatonin is extremely safe, even at very high doses. Some cancer patients take as much as 300 mg daily without any problems.

Dr. Reiter also recommended that people should experiment when they take melatonin. “Start by taking it 20 minutes before bed,” he said. “If that doesn’t work quickly enough, try an hour, or even two. Everyone is different. When you find what works, take it at the same time each night.”

Side Effects of Melatonin

Some patients have told me they experience a hangover or brain fog effect when they take melatonin. A few who suffered with depression said they felt more depressed.  Dr. Reiter suggested that in those cases, to use a dosage of less than 1 mg, such as 200 mcg.

Dr. Reiter noted that in clinical trials with melatonin, you never see any mention of such unusual responses, which may also include hyperactivity. He attributed this to a potential reaction with other ingredients in the pills that are available commercially. Researchers, by contrast, use only pure melatonin in their studies. Still, he said, there could be some people with unique chemical sensitivities.

Other Benefits of Taking Melatonin

In my research, I’ve read a good deal about melatonin’s potent antioxidant properties. I asked Dr. Reiter for his take on how these properties could benefit the cardiovascular system.

He sees melatonin as working on multiple levels. First, he said, melatonin is quickly distributed throughout the body. It enters cardiac cells with ease and has the ability to cross the blood brain barrier. Most importantly, melatonin gets inside the mitochondria, the “power plants” within cells where energy is produced. Few nutraceuticals can penetrate to this point, which makes melatonin especially useful.

A huge number of free radicals are produced as a byproduct of the mitochondrial energy-production process. Free radicals, as a reminder, are molecules with unpaired electrons that snatch electrons away from other molecules, setting off a biochemical chain reaction that potentially leads to inflammation and damage to cells and tissue. Unless the body controls free radical activity, the damage can be extensive − even deadly, over time. Melatonin helps scavenge for, and neutralize, free radicals. It also has an anti-inflammatory effect.

“We think these protective actions have potential applicability for individuals with cardiovascular disease,” Dr. Reiter said.

Furthermore, recent studies have shown that at least some of melatonin’s antioxidant effects are due to its metabolites, or the additional compounds melatonin creates when it interacts with free radicals. This increases melatonin’s ability to fight against oxidation in cells.

Dr. Reiter added that in animal experiments, melatonin has been shown to sharply reduce local tissue damage caused by strokes and heart attacks.

“I’ve told my wife that if I have a cardiovascular event, I want to swallow as much melatonin as I can get into me,” he said.

For the strongest antioxidant effect, Dr. Reiter suggested using melatonin throughout the day in addition to before bedtime. The only catch is that you need to use very small amounts (250–500 mcg) to avoid getting drowsy. Then take your larger regular amount at night.

You can buy melatonin in health food stores as a stand-alone supplement or as part of many sleep formulas.

The Mars-Melatonin Connection

During our conversation, Dr. Reiter shared with me the curious way he became involved with melatonin. In 1964, after obtaining his PhD, he spent two years in the military at the Army Chemical Center near Baltimore. Of course, back then during the Cold War, there was tremendous competition between the Soviet Union and the U.S. to put manned flights into space. Dr. Reiter became involved in the human aspect of that activity. Specifically, he and another colleague were assigned to find the biochemical that causes hibernation in animals.

“Hibernation?” I asked Dr. Reiter. “What does that have to do with the space program?”

The planners, he said, were concerned about the day-in-and-day-out details of astronauts being in space for up to six months, the estimated time for a trip to Mars. Such a mission would require a massive amount of food and water, generate a comparable amount of human waste, and involve endless hours of boredom while flying through space. The idea was to put the astronauts into a state of suspended hibernation and then awaken them before they needed to land the spacecraft.

The researchers never did find the key to hibernation − but they did discover that the amount of melatonin, which is produced in the pineal gland just behind the forehead, was regulated by light and dark. With that discovery, Dr. Reiter’s career as a melatonin explorer was launched.

Can’t Sleep? Don’t Turn on the Light

Darkness − not sleep, as many people think − is what causes the body to produce melatonin. Exposure to light, including nightlights, short-circuits this process.

Still, it’s difficult to wean yourself entirely of light at night. That’s why it’s best to use red bulbs in nightlights. Red light doesn’t interfere with melatonin like other colors of light do − especially the blue bulbs that sometimes come with nightlights.

And if you still can’t sleep?

Whatever you do, don’t get up and read a book or open the refrigerator to pull out a snack. According to Dr. Reiter, “if you do you that, you are producing the equivalent of jet lag. Even if you lay in bed in darkness and don’t sleep, you still produce melatonin. If you wake up in the middle of the night and find you can’t readily go back to sleep, take some melatonin − a reduced amount − but don’t turn on the light.”

© 2013 HeartMD Institute. All rights reserved.

Leave a Reply


  1. Bob

    on October 9, 2013 at 5:25 am


  2. Bob

    on October 9, 2013 at 5:32 am


  3. Bob

    on October 9, 2013 at 5:34 am


  4. Ruth

    on January 28, 2014 at 2:28 pm

    I have tried 1 mg of melatonin, but it gives me a headache, just like the 3 mg pill. The benefits sound great, especially lowering blood pressure, but I don’t like waking up with a headache.

    What is the secret?

  5. Debbie

    on January 5, 2015 at 5:08 am

    what should i do if I am experiencing light headed dizziness and a lower / dip in blood pressure?
    I am currently taking 3mg of melatonin. Should I stop taking melatonin? It helps me sleep, i have a time unwinding or relaxing with out melatonin. But i am afraid of my blood pressure being too low. As this can be dangerous, low blood pressure that is.

  6. Peter J. Danyliw

    on May 13, 2015 at 7:23 pm

    Thank you Dr. For this great article! I am just starting a regimen of the beta blocker Carvedilol (3.125mg twice daily).Did this as a LAST resort to control BP to keep my job w/CDL Lic. Wish I stumbled upon this article earlier, and had done some experimenting with melatonin before going on a pharmaceutical poison.

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  8. Linda Johnon

    on September 22, 2016 at 6:29 am

    Just found this blog about blood pressure and low blood pressure. I have been taking melantonin for 3 yrs. and the last 6 months my BP at nite was very low. I started taken a reduced amt of my BP meds from my heart doctor but every time I thought I needed the BP meds I would take another blood pressure check and it was very low like 90 over60 and heart rate would go down as low as 37. Starting to freak out – I have now read this article and I believe that I probably do not need the Blood Pressure Meds as long as I take the melantonin. I had echo on heart today because of this low blood pressure. Every thing on blood work perfect except closterol an he wants me to do gastric by pass. I do not do well with anesthetic so what pill do I need to get the closterol down? I tried everyone my dr gave me to try and the side effects were horrible. Thanks, Linda

  9. HeartMD Editor

    on September 22, 2016 at 10:35 am

    Hi Linda,

    To lower cholesterol there are many things that can be done and many different approaches to take. We always suggest that you consult with your doctor and work with them to find a solution. Here are some resources from HeartMD Institute regarding cholesterol that you may find helpful:

    VAP Test Discontinued! Test Your Cholesterol Particle Size With These Alternatives
    Let’s Clear Up the Cholesterol Confusion
    Rethinking Statins

    Additionally, please see Dr. Sinatra’s book: The Great Cholesterol Myth.

    HMDI Editor

  10. desmond Aboagye

    on January 5, 2017 at 9:46 pm

    Consumer Reports has an article that suggests that taking Melatonin and any high blood pressure med is never a good combination. What is your take on this?

  11. Kathy U.

    on March 30, 2017 at 8:13 pm

    My question is the same as Mr. Aboagye….my melatonin supplements say not to take them if you take high blood pressure medications. I currently take 40 mg of Bystolic daily—the doctor recommended taking them at night. I have been taking 1 to 3 mg of Melatonin for the last week or two to help me get to sleep.

  12. Russell Eaton

    on May 11, 2017 at 3:16 pm

    I’ve been taking 3 mg of melatonin every day for the last 20 years. I feel it has kept me young and healthy.

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