Does potassium lower blood pressure?

Yes, potassium can lower blood pressure, and the effect is meaningful in people who already have hypertension. Pooled trials point to a drop of around 5 mmHg systolic. The important caveat is that potassium is not safe for everyone, and food is not the same as supplements.

That caveat is the part most articles skip. For most healthy adults, eating more potassium-rich food is a good move. For people with kidney disease, or on certain blood pressure medicines, the same advice can be harmful.

Does potassium lower blood pressure? What the trials show

The clearest answer comes from a systematic review by Aburto and colleagues, published in the BMJ in 2013 and funded by the World Health Organization. Pooling 22 randomised controlled trials, it found that increasing potassium intake lowered systolic blood pressure by 3.49 mmHg on average, and diastolic by 1.96 mmHg.

The subgroup result matters more. In people who already had high blood pressure, the reduction was 5.32 mmHg systolic (95% confidence interval 3.43 to 7.20) and 3.10 mmHg diastolic. Where blood pressure was already normal, the change was not statistically significant. The same review linked higher potassium intake to a 24% lower risk of stroke.

More is not automatically better. A 2020 dose-response meta-analysis by Filippini and colleagues in the Journal of the American Heart Association, covering 32 trials, found the relationship is nonlinear and concluded that excessive supplementation should be avoided, particularly in certain groups.

How much potassium you need, and where to get it

To prevent or treat high blood pressure, the American Heart Association recommends 3,500 mg to 5,000 mg of potassium daily, ideally from diet. The UK reference intake for adults is 3,500 mg a day, according to the British Heart Foundation.

Food gets you there. The AHA puts a medium banana at about 451 mg and half a cup of plain cooked sweet potato at 286 mg. The BHF puts a medium boiled potato at around 639 mg and an 80 g serving of spinach at 545 mg. This is part of why the DASH diet works.

Most of the potassium blood pressure trials used potassium chloride supplements, which is why their numbers look so tidy, but that is not the route to copy. The AHA says a moderate-dose supplement is something a healthcare professional may recommend if diet is not enough, not something to start unprompted. The BHF advises against unprescribed potassium supplements outright.

Who should be careful with potassium

Your kidneys clear excess potassium from your blood. When that process is impaired, potassium builds up, a condition called hyperkalaemia, which can affect heart rhythm.

The US National Institutes of Health Office of Dietary Supplements states that in people with impaired urinary potassium excretion, whether from chronic kidney disease or from medicines such as ACE inhibitors or potassium-sparing diuretics, even dietary potassium below the adequate intake can cause hyperkalaemia. The British Heart Foundation names the same groups: ACE inhibitors, angiotensin receptor blockers (ARBs), and diuretics such as spironolactone and eplerenone.

If that includes you, ask your doctor or pharmacist before increasing your potassium. The AHA warns that levels often have to be very high before symptoms appear, and that those symptoms can include nausea, vomiting, an irregular heart rate, fainting, and muscle weakness.

The salt substitute trap

Potassium-based salt substitutes swap some sodium chloride for potassium chloride, cutting sodium and adding potassium at once. The evidence is strong. The Salt Substitute and Stroke Study, published by Neal and colleagues in the New England Journal of Medicine in 2021, followed around 21,000 adults in rural China for roughly five years. Those using a substitute of 75% sodium chloride and 25% potassium chloride had a 14% lower rate of stroke and a 12% lower death rate.

The detail the headlines leave out: people with chronic kidney disease or at risk of hyperkalaemia were excluded from that trial, so its safety result does not extend to them. The AHA advises checking with a healthcare professional before using a salt substitute.

When to see a doctor

• Ask before changing anything if you have kidney disease or diabetes, or take an ACE inhibitor, an ARB, or a potassium-sparing diuretic. This covers salt substitutes as much as supplements.
• Book an appointment if your home averages sit at 130/80 mmHg or higher, or are rising.
• Recheck, then call, if a reading is higher than 180/120 mmHg. The American Heart Association advises waiting a minute and taking it again. If it is still that high with no symptoms, contact your healthcare professional promptly.
• Call emergency services if a reading that high comes with chest pain, shortness of breath, numbness, weakness, vision changes, or difficulty speaking.
• Never stop or adjust a prescribed blood pressure medicine on your own.

This article is general information and does not replace personalised medical advice.

Frequently asked questions

How much potassium should I eat to lower blood pressure?

The AHA recommends 3,500 mg to 5,000 mg a day, ideally from food, and the UK reference intake is 3,500 mg. There is no separate “blood pressure dose”, and going higher needs medical advice.

Are potassium salt substitutes safe?

For many people, yes. But the trial behind the benefit excluded people with chronic kidney disease or a risk of hyperkalaemia, so check first if you have kidney disease or take medicines that affect potassium.

How long does potassium take to lower blood pressure?

Trials in the 2013 BMJ review ran for at least four weeks. Change is gradual, so a run of readings over several weeks tells you more than one measurement.

The bottom line

Potassium does lower blood pressure, by roughly 5 mmHg systolic in people who already have hypertension, and food is the sensible way to get it. Treat it as a habit worth building rather than a cure, and check with your doctor first if you have kidney disease or take any of the medicines above. For the wider picture see how to lower blood pressure, how much sodium is too much, and does magnesium lower blood pressure?

---

Sources: Aburto NJ et al., BMJ 2013;346:f1378; Filippini T et al., J Am Heart Assoc 2020;9:e015719; Neal B et al., NEJM 2021 (Salt Substitute and Stroke Study); American Heart Association (Potassium Benefits; Understanding Blood Pressure Readings); NIH Office of Dietary Supplements (Potassium); British Heart Foundation.

This is educational information, not medical advice. If you have kidney disease or take blood pressure medication, speak with your doctor before changing your potassium intake.

Last reviewed: September 2026

Start this habit in CardioVibe and watch your readings build into a trend you can actually read.