Do supplements lower blood pressure?
A few do, by a few points. Beetroot juice and magnesium lowered it in trials. But the one mineral a UK supplement label may say helps blood pressure can be risky with some tablets.
On this page
Do supplements lower blood pressure?
A few do, a little. In trials, beetroot juice and magnesium cut the top number (systolic) by 2 to 7.7 points. Points here are mmHg, the unit on your monitor.
That makes them a small extra, not a swap. Blood Pressure UK says herbal remedies and fish oil shouldn’t replace the treatment your doctor prescribes.
| Supplement | Fall in the top number | Good to know |
|---|---|---|
| Beetroot juice (nitrate) | 4.4 in 2-hour to 15-day trials. 7.7 over 4 weeks in people with high blood pressure. | Nitrates are also in spinach, celery and kale. |
| Magnesium | 2.0, at a typical 368 mg a day for 3 months. | The NHS says 400 mg or less a day from supplements is unlikely to cause harm. |
| Potassium | Lowered it most in people with high blood pressure or a salty diet. | Not recommended unless a doctor prescribes it. |
| Garlic | Not enough evidence to judge. | Only 2 small trials in the main review. |
| Fish oil | A small fall in some studies. | Blood Pressure UK says the evidence is limited. |
| Hawthorn, hibiscus, ginkgo | Too little research to know. | Some herbs can interact with other medicines. |
Sources: Siervo 2013; Kapil 2015; Zhang 2016; Filippini 2020; Cochrane; Blood Pressure UK; BHF; NHS
Take blood pressure tablets? Ask your pharmacist before you add any of these.
How much do beetroot juice and magnesium lower blood pressure?
Beetroot juice did best in a UK trial of 68 people with high blood pressure. Half were already on medicines.
A 250 ml glass a day for 4 weeks cut clinic readings by 7.7/2.4 mmHg.
Shorter trials found less. Across 16 small trials, the top number fell by 4.4. The authors say the results need testing in longer trials.
Magnesium gave a smaller fall. In 34 trials, a typical 368 mg a day for 3 months cut blood pressure by 2.0/1.8 mmHg.
Sources: Zhang 2016; Siervo 2013; Kapil 2015
Say your clinic reading is 150. Even a 7.7 fall leaves it above the NHS line for high blood pressure, 140/90 or higher.
Trying magnesium? Keep supplements to 400 mg or less a day. Higher doses for a short time can cause diarrhoea.
More in can you take too much magnesium.
Do garlic, fish oil or herbal remedies work?
Nobody can say yet for garlic. The main review found just 2 small trials, with 87 people. The fall they saw sat within the usual ups and downs of blood pressure readings.
Fish oil gave a small fall in some studies. Blood Pressure UK says the evidence is limited and the effects are small.
Hawthorn, hibiscus and ginkgo have had only a small amount of research. Blood Pressure UK says natural doesn’t mean safe. Some herbs can interact with other medicines and be harmful.
| Nutrient | Approved blood pressure claim? | Rule |
|---|---|---|
| Potassium | Yes | The food must be at least a source of potassium. |
| Fish oil (EPA and DHA) | Yes | Only if it gives 3 g of EPA and DHA a day. |
| Less salt (sodium) | Yes | The food must be low or reduced in salt. |
| Magnesium | No | Its approved claims are about things like muscles and tiredness. |
| Garlic and beetroot | No | No approved blood pressure claim. |
Source: GB health claims list
Even the approved claims only say they help maintain normal blood pressure. None says it lowers high blood pressure. So read the label for that wording, and treat bigger promises with care.
Is it safe to take supplements with blood pressure tablets?
Not always. That one mineral from the top of the page is potassium.
Too much potassium can affect the rhythm of the heart. The BHF says this is especially dangerous with kidney problems or certain water tablets.
Blood Pressure UK says potassium supplements are not recommended unless a doctor prescribes them. The NHS says older people should not take them unless a doctor advises it.
Low-sodium salts count too, as they swap sodium for potassium. See are salt substitutes safe and potassium supplements.
Take ramipril, a common blood pressure tablet? The NHS says to tell your doctor about medicines that raise potassium, such as the water tablets spironolactone, triamterene and amiloride, and potassium. Herbal remedies are generally not tested with other medicines.
Before you start a blood pressure supplement
- Tell your GP or pharmacist about every supplement and herbal remedy you take.
- Don’t take potassium supplements unless a doctor has prescribed them.
- Have kidney problems? Ask your doctor before using a potassium-based salt substitute.
- Keep magnesium supplements to 400 mg or less a day.
- Keep taking your blood pressure tablets. If you stop, your blood pressure will go back up within a few weeks.
Sources: Blood Pressure UK; BHF; NHS; NHS: ramipril
Never stop or change a prescribed medicine without your prescriber.
What lowers blood pressure more reliably?
Everyday changes, and medicine if you need it. The NHS high blood pressure page lists lifestyle changes and medicines. It doesn’t suggest any supplement.
NHS changes that can help lower blood pressure
- Eat a healthy, balanced diet, and get your potassium from fruit and vegetables.
- Build up to at least 150 minutes of exercise a week.
- Lose weight if you’re overweight.
- Avoid salty food and adding salt to your meals.
- Avoid drinking more than 14 units of alcohol a week on a regular basis.
- Go easy on coffee, tea and cola, and don’t smoke.
Sources: NHS: high blood pressure; BHF
Pick one this week, like no salt at the table. For which exercise helps, see exercise and blood pressure.
To see if anything is working, learn how to check your blood pressure at home.
When to speak to a GP
High blood pressure does not usually cause any symptoms. Speak to a GP or pharmacist if:
- You want to take a supplement and have kidney problems or take blood pressure tablets.
- You think you might have high blood pressure, or you’re 40 or over and haven’t had a check for more than 5 years. Get checked at a pharmacy or GP surgery.
- You often have headaches or blurred vision, or chest pain that comes and goes, or other symptoms you’re worried could be caused by high blood pressure. The NHS says ask NHS 111.
- Call 999 if you get sudden chest pain or discomfort that does not go away (it can feel like squeezing, pressure, burning or indigestion), pain spreading to your arm, neck, jaw, stomach or back, or chest pain with sweating, feeling sick, light-headed or short of breath.
With those 999 signs, do not drive yourself to A&E. To understand your numbers, see blood pressure readings explained.