Quick answer

Potassium is a mineral every cell needs for fluid balance, nerve signals and muscle contraction. Adults need 2,600 to 3,400 mg a day, and most get less from food. A US supplement usually holds 99 mg or less, about 2% of the Daily Value, so food does most of the work.^1,2

Key facts

Average intake from food is about 3,016 mg a day for US men and 2,320 mg for women.²
Among people who take a supplement with potassium, it adds about 87 mg a day on average.²
The body absorbs about 85% to 90% of the potassium in food.²
No upper limit is set for healthy people, but several common medicines can push blood potassium too high, so ask before adding any.^1,2

What potassium does

An adult weighing 175 pounds has about 140 g of potassium in the body, almost all of it inside cells.²

Inside cells, potassium is about 30 times more concentrated than in the fluid around them. Cells spend energy pumping it in, and that difference is what lets nerves send signals, muscles contract and the kidneys do their work.²

Potassium and sodium work as a pair. Sodium sets the volume of fluid outside cells, including blood plasma, and potassium the volume inside them.²

Potassium leaves the body mainly in urine, with some in stool and a very small amount in sweat.²

What the evidence shows

Each claim below carries a grade and the amount behind it. Neither amount is one a typical US supplement provides.²

Contributes to normal muscle function and normal functioning of the nervous system*^1,2,3

Moderate evidence

A long-established role of the mineral. NIH explains that the difference in potassium concentration across cell membranes is required for nerve transmission and muscle contraction, and the EU permits the statements that potassium contributes to normal muscle function and to normal functioning of the nervous system. It does not mean that extra potassium changes muscle or nerve performance in people who already get enough, and no trial reviewed here tested that.

Amount studied: Adequate intake from all sources: 2,600 mg a day for women and 3,400 mg for men

May help maintain bone density in adults over 65 at about 2,300 mg a day as potassium citrate; results are mixed*^2,4,5

Early evidence

NIH says people who get more potassium from fruits and vegetables tend to have higher bone mineral density, but only a few trials have tested supplements and they disagree. In 201 healthy adults over 65 who also took calcium and vitamin D, 60 mEq of potassium citrate a day (about 2,346 mg of potassium) raised spine bone density 1.7% more than placebo over 2 years. In 276 women aged 55 to 65, 18.5 or 55.5 mEq a day (about 723 or 2,170 mg) for 2 years did not slow bone turnover or raise bone density. The proposed effect depends on alkaline forms such as citrate or bicarbonate, not potassium chloride, the most common supplement form.

Amount studied: About 723 to 2,346 mg of potassium a day as potassium citrate, for 2 years

Much of the potassium research looked at outcomes this site does not cover, using about 780 to 4,700 mg a day, mostly as potassium chloride, or diets rich in fruits and vegetables. Those findings are not graded here.²

How much you need

Women need about 2,600 mg of potassium a day from all sources, 2,900 mg during pregnancy and 2,800 mg while breastfeeding.^1,2

Men need about 3,400 mg of potassium a day from all sources.^1,2

The Daily Value used on food and supplement labels is 4,700 mg of potassium for adults and children 4 and older.²

These adequate intakes, updated in 2019, count food, drink and supplements together. They do not apply to anyone whose kidneys or medicines limit how much potassium they can pass.²

What a supplement adds

Most potassium-only supplements contain up to 99 mg of potassium per serving, about 2% of the Daily Value. Multivitamins that include potassium typically have about 80 mg.^1,2

So a supplement changes little. A medium banana has 422 mg, more than four 99 mg servings, and NIH found that supplement use does not significantly raise total potassium intake among US adults.²

Why many makers stop at 99 mg has to do with FDA safety rules for potassium medicines, set out in the safety section below.²

Forms

Potassium chloride is a common form in supplements and the form used in salt substitutes. It is not the form found in fruits and vegetables, which contain potassium phosphate, sulfate, citrate and others.^1,2

Supplements also use potassium citrate, phosphate, aspartate, bicarbonate and gluconate. Research has not shown that any one form is better than the others.^1,2

Food sources

Dried apricots (755 mg per half cup), cooked lentils (731 mg per cup), mashed acorn squash (644 mg per cup), prunes (635 mg per half cup), raisins (618 mg per half cup) and a medium baked potato (610 mg) are among the richest common sources.²

Milk, coffee, tea, other nonalcoholic drinks and potatoes supply the most potassium in the diets of US adults.²

Whole-wheat flour and brown rice are much higher in potassium than white flour and white rice.²

What's in ours

What’s in ours

Creatine + Electrolytes: Potassium, 200 mg per serving, from the label

Creatine + Electrolytes carries potassium alongside sodium and creatine. Its amount is far below the amounts behind the claims above, so we make no potassium claim for it.

Who should not take potassium without a doctor

No tolerable upper intake level is set for potassium, because high intakes from food have not been shown to harm healthy people with normal kidney function. That does not apply to people whose kidneys or medicines limit how much potassium they can pass.^1,2

Too much potassium in the blood (hyperkalemia) can cause muscle weakness, paralysis, heart palpitations, a burning or prickling feeling in the hands and feet, and irregular heart rhythms that can be life threatening. It can also cause no symptoms until it is severe.²

Potassium salts in some oral medicines have been linked to small-bowel lesions that caused obstruction, bleeding and perforation. FDA rules for these medicines cover tablets with 100 mg or more of potassium, which is why many supplement makers stop at 99 mg. FDA has not ruled on whether supplements above 99 mg need a warning.^2,6

Ask your pharmacist or doctor first

ACE inhibitors such as lisinopril and angiotensin receptor blockers (ARBs) such as losartan reduce the potassium lost in urine and can make blood potassium too high (hyperkalemia), especially in people with kidney problems. Their labels list potassium supplements and potassium-containing salt substitutes among the risks, and the labels and MedlinePlus tell people to check with their doctor before using them.^1,2,7,8,9,10

On the medicine's label

Ask your pharmacist or doctor first

Diuretics move potassium in opposite directions. Potassium-sparing diuretics such as spironolactone and amiloride keep potassium in the body and can raise it too high. Loop and thiazide diuretics such as furosemide and hydrochlorothiazide increase the potassium lost in urine and can lower it too far; their labels say potassium supplements or potassium-rich foods may be needed, as directed by the prescriber.^1,2,11,12,13

On the medicine's label

Do not add potassium if you take spironolactone, amiloride or triamterene, unless your doctor has told you to^11,14
Ask first if you have kidney disease, type 1 diabetes, heart failure, liver disease or adrenal insufficiency²
Ask first if you take an ACE inhibitor, an ARB, any diuretic or NSAID pain relievers regularly^1,14
Ask first if you are pregnant or breastfeeding

Salt substitutes can hold 440 to 2,800 mg of potassium per teaspoon, far more than any supplement. Talk to your doctor before using one if you have kidney disease or take a medicine that affects potassium.^1,2

Questions people ask

Do men need more potassium than women?

Yes. The adequate intake is 3,400 mg a day for men and 2,600 mg for women, from food and drink combined. US men average about 3,016 mg from food and women about 2,320 mg, so both fall short on average.²

Is a potassium supplement better than a banana?

Not for the amount. A medium banana has 422 mg, while most supplements hold 99 mg or less. Fruits and vegetables also bring potassium in forms such as citrate and phosphate, rather than the chloride used in many supplements.²

Why do potassium supplements stop at 99 mg?

Many makers stop there because FDA rules for potassium salt medicines cover tablets with 100 mg or more, after reports of small-bowel injuries with coated potassium tablets. FDA has not ruled on whether supplements above 99 mg need a warning.^2,6

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Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.