Supplements for High Blood Pressure

Some people are taking boatloads of supplements, constantly looking for the magic pill. Others are completely skeptical of supplements, thinking they’re just a hoax. The truth is really somewhere in the middle. But make no mistake about it – there are some very potent, proven supplements out there that can help you lower your blood pressure. Likewise, there are also tons of supplements that are unproven, and by the end of this module, you’ll know what works, what doesn’t, and what we don’t know.

Here’s what we’ll cover in this module:

  • Two myths about supplements
  • Three reasons why I REALLY like supplements
  • How to find the right dose
  • Effective supplements for lowering your blood pressure 
  • Ineffective supplements for lowering your blood pressure 
  • Unproven supplements
  • How to combine supplements

But before we get to it, I have to do the obligatory disclaimer: I don’t know you. I don’t know your health status, what other supplements and medications you are taking, and other pertinent factors. So before you start taking any of the supplements in this module, speak to a pharmacist first. A lot of people make the mistake of thinking “supplements are natural, therefore they can’t do any harm.” And boy, are they wrong. If you’re taking a blood pressure-lowering medication, and you combine that with a supplement that lowers your blood pressure as well, you might have a combined effect, and your blood pressure would drop too low. If it drops too low, you might faint.

Or, a supplement that you’re taking may negate the effects of a medication that you’re taking, so your blood pressure wouldn’t lower at all.

So again, speak to a pharmacist before you start taking any of these supplements.

With that disclaimer out of the way, let’s get to it!

Supplement Myths

Myth #1: Supplements Don’t Work

For someone to believe this one, they’d really have to completely ignore the mountains of research done over the decades that supplements do work. That’s not to say that every single supplement on the market works. And that’s not to say that every supplement works in 100% of people. But to make a blanket statement that there isn’t a single supplement out there that works is just plain false.

Then there’s the cousin – “it’s just a placebo effect.” First of all, no it’s not. In double-blind, placebo-controlled studies, the term “placebo-controlled” means that one group of participants in the study are getting a placebo, and the other is getting the real supplement, and consistently, the right supplement outperforms the placebo. Therefore it can’t be the placebo effect.

Second of all, even if it was a placebo effect, so what? The placebo effect is a real, measurable effect. If your blood pressure went down, whether due to something real, or something in your mind, who cares about the reason? You’re forgetting the main point – your blood pressure went down!

Myth #2: You Have to Make Dietary Changes First

False again. In most studies, researchers specifically tell participants not to make any dietary changes when they’re taking supplements. Why? Because if you start taking a supplement, and you change your diet at the same time, you don’t know if the effect was caused by the supplement, by the diet, or both.

And even in the absence of any dietary changes, some supplements work. Again, that’s not to say that every supplement works (we’ll cover what works and what doesn’t later in this module), but those that do work do so in the absence of any dietary changes.

Three Reasons Why I Really Like Supplements

As you can tell, I’m a big fan of supplements. There are 3 reasons for this. In no particular order:

Reason #1: Effectiveness

As I mentioned in the previous section, the supplements that work do so in their own right, in the absence of any dietary changes. Would you get an additive effect if you combined them with changes in exercise and nutrition? Sure. But you still get anywhere from a moderate to a large effect on your blood pressure without any other changes.

Reason #2: Compliance

If you’ve ever been on a diet before, you know that dietary changes are hard. If you’ve been eating a certain way for 40, 50, 60 years or more, it’s very hard to change those long-standing habits.

But taking a pill, powder or liquid? That’s easy! Most people have near- 100% compliance with that. Whereas dietary changes, given that 80-95% of people who lose weight regain it, don’t have anywhere near the same compliance level.

Reason #3: Speed

Some supplements work quickly (in a matter of hours), and other supplements take a few weeks of taking them regularly to have any effect. But even if a supplement takes a month to work, that’s relatively fast for most people.

How to Find the Right Supplement Dose

With any supplement, you want to make sure you’re taking a dose high enough that it’s effective, but low enough that it doesn’t cause any adverse effects.

There are a couple of factors that go into figuring out the optimal dose for you:

Factor #1: your own bodyweight. The more you weigh, the more of a dose you need.

Factor #2: your personal reactivity to it. Some people are highly responsive to supplements, and others aren’t.

To figure out the right dose for you, here’s a step-by-step process you should use:

Step 1: start at the dose that it says on the label of whatever supplement you’re taking. Stay at that dose for 2 weeks. Note if it had the desirable effect (did it lower your blood pressure?)

Step 2: raise the dose by the smallest possible increment for another 2 weeks. Note if after an additional 2 weeks the effect increased, or it stayed the same. If the effect stayed the same, go back to the dose used in step 1. If the effect increased, move on to step 3

Step 3: keep repeating step 2 until either the effect has maxed out (no larger drops in blood pressure despite larger doses), or you’ve reached the maximal safe dose.

Step 4: after about 1-2 months, try reducing the dose by the smallest possible increment. If the blood pressure is unchanged after 2 weeks at the lower dose, reduce it again by the smallest possible increment. However, if the blood pressure went up after you reduced the dose, raise it back up again.

If you want to add an additional layer of certainty, you can speak to your doctor or naturopathic doctor about running nutrient testing (one of the most standard tests for it is called an “organic acids profile”).

Effective Supplements

Now, we get to the fun part: the supplements that work. The supplements listed here have been shown to work by multiple studies, in humans. I emphasize “in humans”, because a lot of supplements go to market prematurely. They’re shown to work in either mice/rats, or petri dishes. But not people. Each supplement listed in this section has been shown to work in people, across more than 1 study.


One large meta-analysis36 showed a blood pressure reduction of 8.2/4.5 mmHg from supplementing with potassium. Another meta-analysis37found similar reductions.

How it works: if you’ve read the module on nutrition, then you already know how it works. If you haven’t, here’s the mechanism: when you supplement with potassium, it keeps sodium in balance, which in turn prevents excess water from accumulating inside the arteries. Additionally, potassium opens up blood vessels in its own right.

Upper limit: 2500 mg/day.

Symptoms of toxicity:

  • Heart palpitations
  • Nausea
  • Vomiting
  • Difficulty breathing
  • Numbness and tingling


One narrative review, showedabloodpressurereductionofabout4/3 mmHg from magnesium supplementation. Though to be fair, the average dose of magnesium used was about 370 mg/day. Higher doses usually show greater reductions.

Types of magnesium that are effective: magnesium glycinate, magnesium orotate, and magnesium taurate.

How it works: magnesium helps the smooth muscle surrounding arteries relax, which increases the space inside an artery.

Upper limit: 350 mg of actual magnesium. The reason I say “actual” magnesium is because when you get 350 mg of magnesium in supplements, it’s not all magnesium. The majority of it is the chelate. So when you get 350 mg of magnesium glycinate, the label will break down how much of the dose is actual magnesium, and how much is other “stuff.”

Symptoms of toxicity:

Allicin (AKA Aged Garlic Extract)

In an analysis review, when people with high blood pressure supplemented with aged garlic extract, their blood pressure dropped by an average of 16.3/9.3. Quite impressive, right?

How it works: if you’ll remember from module 2, garlic has a number of different mechanisms:

  • It’s a natural beta blocker – it blocks the receptors for adrenaline, preventing the blood vessels from closing
  • It inhibits the hormone angiotensin, which causes the constriction of blood vessels. What you have done is you blocked constriction and you get dilation.
  • It prevents the smooth muscle surrounding arteries from contracting
  • It contains nitric oxide, which also dilates blood vessels

Upper limit: according to Examine.com40, garlic extract should not exceed 5% of the diet. So that’s 17 grams for a 150-pound person, 22.7 grams for a 200- pound person, and 28.4 grams for a 250-pound person.

Symptoms of toxicity: unknown 

Nitrate/Beetroot Juice

In two different meta-analyses (one on the effects of dietary nitrate supplements on blood pressure41 and another on Inorganic Nitrate and beet root juice on blood pressure42,), nitrate supplementation lowered blood pressure by about 4/2 mmHg, and there was no difference between using it for 3 days and 3 months.

How it works: supplemental nitrate gets converted into another chemical called “nitric oxide”, which causes the smooth muscles surrounding arteries to relax, and that opens up the arteries.

Upper limit: 12.8 mg/kg

Symptoms of toxicity:

  • Weakness
  • Shortness of breath without much exertion
  • Loss of coordination

Olive Leaf Extract

In a study, olive leaf extract lowered blood pressure by11.5/4.8mmHg, when taken at a dose of 500 mg, twice a day.

How it works: olive leaf extract inhibits the hormone angiotensin, which causes the constriction of blood vessels. So you block constriction and you get dilation.

Upper limit: unknown. 

Studies have gone up to 1000 mg/day, without noting any symptoms of toxicity

Symptoms of toxicity: unknown, but theorized that it can cause stomach pain and headaches.

Greens Drinks (Fruit and Vegetables Powders)

In a recent research article, a greens drink lowered blood pressure by 12.4/7.1 mmHg when taken daily for 90 days. This is without a change/loss in weight.

How it works: because greens drinks are a mix of different vegetables and fruits, they have all the mechanisms of action of the previous supplements:

  • They are natural beta blockers – they block the receptors for adrenaline, preventing the blood vessels from closing
  • They inhibit the hormone angiotensin, which causes the constriction of blood vessels; So you block constriction and you get dilation.
  • They prevent the smooth muscle surrounding arteries from contracting 
  • They contain nitric oxide, which also dilates blood vessels

Upper limit: unknown

Symptoms of toxicity:

  • Diarrhea
  • Bloating
  • Indigestion ● Fatigue

Fish Oil

One meta synthesis45 found that when people with high blood pressure supplemented with fish oil at a dose of 3-7 g/day, their blood pressure dropped by 2.9/1.6 mmHg. And when they supplemented with 15 g/day, their blood pressure dropped by 8.1/5.8 mmHg.

Because fish oil quality varies so much from company to company (in some stores, fish oil is already rancid by the time it’s on the shelf… only you don’t know it, because it’s covered up by the smell of lemon or orange), I’ll tell you what to look for.

  • You want an opaque container
  • You want something that is stored in refrigerated temperatures (room temperature or higher speeds up the rancidity of oil)
  • For smaller doses (under 5 g/day), capsules will do. For larger doses (over 5 g/day), liquid is better

How it works: according to one study on Omega-3 fatty acids46, fish oil lowers blood pressure by activating potassium channels (that means that the cells can take in more potassium, which counterbalances sodium).

Upper limit: unknown.

Symptoms of toxicity:

  • Oil leakage out of anus 
  • Bleeding
  • Diarrhea
  • Insomnia
  • Indigestion ● Vomiting

CoEnzyme Q10 (CoQ10)

CoQ10 is an antioxidant and a natural chemical found in cells. Together with other processes and chemicals, it’s responsible for energy production.

One meta-analysis47 found that people with high blood pressure who supplemented with CoQ10 lowered their blood pressure by as much as 17/10 mmHg. The full effects take several months to be actualized, and the doses varied from 75-360 mg/day. A study48 on the effect of coenzyme Q10 in physical exercise, hypertension and heart failure, found fairly similar results (blood pressure drops around 16/10 mmHg).

How it works: CoQ10 inhibits the hormone angiotensin, which causes the constriction of blood vessels. So you block constriction and you get dilation. Additionally, it stabilizes calcium channels, preventing calcium from binding to the calcium receptors, and causing contraction of the smooth muscles surrounding arteries.

Upper limit: 1200 mg/day

Symptoms of toxicity:

  • Loss of appetite 
  • Heartburn
  • Diarrhea
  • Nausea

Ineffective Supplements

Now you know all the supplements that are proven to lower blood pressure (at the time of this writing). There are also lots of supplements said to lower blood pressure, but either don’t do so by a great extent, or don’t do so at all. That doesn’t mean they have no benefit for other reasons, but as far as blood pressure is concerned, they are proven ineffective (though that doesn’t stop a lot of supplement manufacturers from putting them into blood pressure-lowering formulas, and claiming they work, despite evidence to the contrary).

Grape Seed Extract

Grape seed extract is one of those where we’re not really sure whether it’s effective or not. One meta-analysis, showed a reduction of 1.54 mmHg, which is not terribly effective. But a different meta-analysis50, showed varying levels of effectiveness (from not effective at all, up to moderately effective), based on dose, how high the blood pressure was to begin with, and how long it was taken for.

How it works: grape seed extract increases nitric oxide in the body, which dilates blood vessels.

Since it’s pretty safe, and you’d like to try it on yourself, to see whether it works for you or not, here’s what you need to know:

Upper limit: unknown, but to my knowledge, the highest used dose in research was 2000 mg/day. Symptoms of toxicity:

  • Dizziness 
  • Nausea
  • Headache


To be honest, arginine is straddling the border between effective and ineffective, but my choice was to put it in this section, for a few reasons:

  1. The dose needed for it to lower blood pressure is quite high. Most research sees the best effects at 10-24 grams/day. Most commercially available arginine supplements come in doses of 500 mg. So you’d have to pop 20- 48 pills per day to have a blood pressure-lowering effect.
  2. It doesn’t do so reliably in most people, even at the right dose.
  3. The degree to which it lowers blood pressure isn’t huge. For systolic blood pressure, it’s 2.2-5.4 mmHg. For diastolic blood pressure, it’s 2.7-3.1 mmHg, according to observations51.

How it works: arginine stimulates the body to produce nitric oxide, which dilates blood vessels.

Upper limit: unknown, but most studies don’t go above 20-24 grams/day

Symptoms of toxicity:

  • Diarrhea
  • Low blood pressure 
  • Abdominal pain
  • Bloating
  • Airway inflammation


Citrulline is an amino acid that is a precursor to arginine. But just like arginine’s effect is inconsistent and questionable, so is citrulline’s. In one meta synthesis52, citrulline had no effect on blood pressure.

There’s no upper limit and toxicity listed for citrulline because it’s not effective, so there’s no need to take it.

Folic Acid

Folic acid is one of the B vitamins (B9).

In one narrative review51, high-dose folic acid supplementation lowered blood pressure by only 2.03/0.01 mmHg.

There’s no upper limit and toxicity listed for folic acid because it’s not effective, so there’s no need to take it.

Unproven Supplements

Very often, people confuse “unproven” with “ineffective.” But they’re not the same. Ineffective means “it doesn’t work.” But “unproven” means “we don’t know if it works.” Either studies haven’t been done, or the studies had methodological flaws that make conclusions about effectiveness very difficult.

Fortunately, you don’t care about averages – you care about you. You can do your own “study” on yourself. My first instinct with clients is to recommend what’s proven, and has a high degree of efficacy. But if you want to give these a try, go for it (after a conversation with a pharmacist, of course). You will learn about how these supplements affect your body, faster than it takes to conduct a study.

Hawthorn Extract

Hawthorn is a plant in the berry family. The extract takes the “active ingredient”, thought to lower blood pressure, and standardizes it to a certain dose.

In one systematic review53 on the effects of Hawthorn and blood pressure, researchers saw that the majority (so not all of them) of studies (which is only 4) found it beneficial for high blood pressure, but because of the vast differences in people’s responses and study design, it was difficult to pin down an average by which blood pressure is reduced.

How it works:

  • Hawthorn is an antioxidant
  • Hawthorn stimulates nitric oxide production, which opens up blood vessels
  • To a small extent, it inhibits the hormone angiotensin

Upper limit: unknown, but the highest dose used in research is 1800 mg/day.

Symptoms of toxicity:

  • Nausea
  • Headache
  • Dizziness
  • Fatigue
  • Digestive problems

Valerian Root

To my knowledge, there aren’t any studies on how valerian root affects blood pressure. It’s been studied in areas more to do with things like sleep, PMS, and anxiety. But even there, it hasn’t shown serious effectiveness.

How it works: for things like anxiety, sleep and PMS, it works by stimulating the body to release more GABA (gamma amino butyric acid), which is a neurotransmitter (brain chemical) that causes relaxation. How it works for high blood pressure: we don’t know.

Upper limit: unknown, but the highest dose used in research has been 900 mg/day.

Symptoms of toxicity:

  • Hangover-like feeling 
  • Headache
  • Insomnia
  • Sedation


Carnitine is an amino acid, and supplementally, it comes in 2 forms: l-carnitine, and acetyl-l-carnitine (ALCAR). The only difference is that ALCAR crosses the blood-brain barrier (the blood-brain barrier is a collection of cells that separates the substances in the blood that can get through to the brain, and the ones that can’t).

Very little research has been done on either one when it comes to high blood pressure (the majority of research on carnitine is in the areas of weight loss, exercise and athletic performance. The short version: it’s not terribly effective for any of them), so it’s hard to make any conclusions.

The only study54 which adequately links the variables, that I’m aware of that looked at the effects of ALCAR on high blood pressure showed no effects when taken at a dose of 2000 mg/day for 6 months. In this study, ALCAR was taken together with simvastatin (Zocor), so we don’t know if there was an interaction between the two.

As for L-carnitine, one meta-analysis, showed it to be ineffective in lowering blood pressure when taken at a dose of 2000 mg/day.

How it works: we know how it’s supposed to work for weight loss and exercise tolerance, but it’s still not totally clear the mechanisms by which it’s supposed to lower blood pressure (if it does so at all).

Upper limit: the highest level I’ve seen used in research is 100 mg/kg/day.

Symptoms of toxicity:

  • Diarrhea
  • Vomiting
  • Nausea
  • Abdominal cramping

How to Combine Supplements

You might have looked through this list of supplements, seen which one appeals to you, and starting taking it. But then, you might have had a thought: “if supplement X decreases blood pressure by ___ mmHg, supplement Y decreases blood pressure by ___ mmHg, and supplement Z decreases blood pressure by ___ mmHg, I’ll just take them all at the same time.”

Or you might be a “why choose” type of person, and decided to take all of them.


Usually these supplements are studied in isolation, and how your body would react if you were to take two or more at the same time is unknown. They might have beneficial effects (that’s what you’re hoping for). But they might just cancel each other out. Or they might have synergistic effects, and drop your blood pressure too low, which would make you more prone to fainting, weakness, lethargy, etc.

To intelligently combine supplements, follow these steps: 

Step 1: pick a supplement that you want to try.

Step 2: follow the steps from the section on how to find the right supplement dose

Step 3: once you’ve found the right dose, stay there for 1-2 weeks, or until your blood pressure stabilizes.

Step 4: add another supplement, and repeat step 2

With each new supplement you add, keep monitoring your blood pressure, to see if that supplement works for you (if it lowers your blood pressure more than the supplement(s) that you’re already taking) or if it negates the effects of the previous supplements.

It may be best to work with a medical professional who is knowledgeable when it comes to supplements, for the very important reason that supplements are rarely studied together, so little is known how they interact with each other when more than one is taken at a time.

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