Supplements › Mineral

Potassium

An essential mineral in fruit, vegetables, beans, potatoes and milk that cells, nerves and muscles need. Most studied for blood pressure and kidney stones.

Strongest evidenceHydrationStrong, 514 studies
Median dose in studies60 mmol a dayFrom 59 study groups
Daily need for adults2,600 to 3,400 mg a dayUS: 3,400 mg for men, 2,600 mg for women. EU: 3,500 mg.
Upper limitNone setUS and EU. With kidney disease or some medicines, even food can give too much.
Ask a doctor or pharmacist first

Ask a doctor or pharmacist first if you:

  • have kidney disease: even potassium from food, below the adequate intake, can raise blood potassium too high (hyperkalemia)[1]
  • take an ACE inhibitor (benazepril), an angiotensin receptor blocker or ARB (losartan), or a potassium-sparing diuretic (amiloride, spironolactone): these medicines make the kidneys pass less potassium[1]
  • take a loop or thiazide diuretic such as furosemide: these medicines raise potassium losses, and experts advise checking potassium levels[1]
  • have type 1 diabetes, heart failure, adrenal insufficiency or liver disease: hyperkalemia can also occur with these conditions[1]
  • plan to use a salt substitute: one teaspoon can contain 440 to 2,800 mg of potassium[1]

Overview

What is potassium?

Potassium is an essential mineral that every cell of the body needs. It is the most common positive ion inside cells, and an adult who weighs 175 pounds (79 kg) holds about 140 g of it.[1] Fruit, vegetables, beans, potatoes, milk, meat, fish and nuts all contain potassium.[1] Supplements use potassium chloride, citrate, phosphate, aspartate, bicarbonate or gluconate.[1] Many salt substitutes replace part or all of the sodium chloride in salt with potassium chloride.[1] Potassium iodide, found in some supplements, is a source of iodine, not of potassium.[1]

What is potassium used for?

Potassium supplements are most studied for blood pressure, and potassium citrate for kidney stones. What the best reviews found:

  • Blood pressure. In a 2017 review of 25 trials in 1,163 people with high blood pressure, supplements lowered systolic pressure by 4.48 mmHg and diastolic pressure by 2.96 mmHg.[2][1] A 2013 review saw the effect in people with high blood pressure, but not in people without it.[3]
  • Salt substitutes. In a 2022 Cochrane review of 26 trials, salt substitutes with less sodium, most of them with potassium, probably lowered systolic pressure by 4.76 mmHg and cardiovascular deaths slightly.[4]
  • Stroke. In cohort studies, which follow people for years, a higher potassium intake went with a 24% lower risk of stroke.[3]
  • Kidney stones. In people who already had calcium stones, citrate salts cut the risk of new kidney stones to about a quarter (risk ratio 0.26) in a 2015 Cochrane review of 7 trials.[5] The citrate, not the potassium, is thought to prevent the stones.[1]
  • Bones. In a 2015 review of 14 studies, potassium citrate and bicarbonate lowered calcium loss in urine and a marker of bone breakdown, but did not change bone density.[6]

Blood sugar has not been tested well in trials yet.[1] A 2026 review found higher, not lower, blood potassium after a race in people with exercise cramps.[7]

Is potassium safe?

For healthy people with normal kidneys, potassium from food is not a health risk: the kidneys pass extra potassium into urine.[1] Neither the US nor the EU has set an upper limit.[1][8] EFSA, the EU food safety authority, looked at long-term use in healthy adults. About 3,000 mg a day as potassium chloride supplements, on top of food, caused no adverse effects.[8] The risks are:

  • Hyperkalemia. People with kidney disease, or who take ACE inhibitors, angiotensin receptor blockers (ARBs) or potassium-sparing diuretics, can get high blood potassium even from food.[1] Severe cases can cause muscle weakness, paralysis and heart rhythm problems that can be life threatening.[1]
  • Very high doses. Case reports linked 5,000 to 7,000 mg a day from supplements to effects on the heart in apparently healthy adults.[8]
  • Stomach and gut. Supplements can cause minor stomach and gut side effects.[1] Potassium salts in some medicines have been linked to injuries of the small bowel.[1]
  • Salt substitutes. One teaspoon can contain 440 to 2,800 mg of potassium.[1]

People with kidney disease, heart failure, type 1 diabetes or liver disease, and people who take blood pressure medicines or diuretics, should ask a doctor or pharmacist first.[1]

How it works

Potassium is the most common positive ion inside the body's cells. An adult who weighs 175 pounds (79 kg) holds about 140 g, and most of it is inside cells.[1]

  1. Gut absorption

    The body absorbs about 90% of the potassium in food, mainly in the small intestine, by passive diffusion.[1][8] From a potassium gluconate supplement the body absorbs about 94%, the same share as from potatoes.[1][9]

  2. Into the cells

    After a meal, potassium enters the blood, and cells take it up quickly.[8] A pump in the cell wall, the sodium-potassium pump (Na+/K+-ATPase), keeps the level inside cells about 30 times higher than outside.[1]

  3. Nerves and muscles

    This difference across the cell wall is needed for nerve signals, muscle contraction and kidney function.[1] The body keeps the blood level at about 3.6 to 5.0 mmol/L.[1]

  4. Blood pressure

    A higher intake may lower blood pressure. Potassium widens blood vessels and makes the kidneys pass more sodium into urine, which lowers the volume of blood plasma.[1]

  5. Leaving the body

    The kidneys pass most potassium into urine, and they pass more soon after a meal rich in potassium.[1] Stool carries 10 to 20% of the losses, and sweat a small amount.[8] At least 5 mmol (about 195 mg) leaves in urine every day.[1]

Explainers

Benefits and studies

Each row is one benefit. The square shows the grade and the number of studies. Open a row to see the most trusted studies.

StrongModerateWeakNo trials
BenefitMain effects in studiesStudiesPeople

Dose

The trials in a 2017 blood pressure review gave 30 to 120 mmol of potassium a day (1,173 to 4,692 mg), mostly as potassium chloride.[1] The US adequate intake for adults is 3,400 mg a day for men and 2,600 mg for women. EFSA, the EU food safety authority, sets 3,500 mg for adults.[1][8]

Usual dose

In a 2017 review of blood pressure trials, 30 to 120 mmol a day, mostly as potassium chloride.[1] In a 3-year kidney stone trial, 30 to 60 mEq of potassium citrate a day, which is 1,173 to 2,346 mg of potassium.[10][1] In a bone trial, 60 mEq of potassium citrate a day.[11] One mmol, or one mEq, of potassium is 39.1 mg.[1]

Daily need

The US adequate intake is 2,000 mg a day at 1 to 3 years and 2,300 mg at 4 to 8 years. At 9 to 13 years it is 2,500 mg for boys and 2,300 mg for girls, and at 14 to 18 years 3,000 mg for boys and 2,300 mg for girls. Adult men need 3,400 mg and adult women 2,600 mg. At age 19 to 50 it is 2,900 mg in pregnancy and 2,800 mg when breastfeeding.[1] EFSA sets 3,500 mg for adults, also in pregnancy, and 4,000 mg when breastfeeding. For children it sets 800 mg at 1 to 3 years, rising to 3,500 mg at 15 to 17 years.[8] WHO suggests at least 3,510 mg a day for adults, and recommends more potassium from food.[12]

Form

Supplements most often contain potassium chloride. Citrate, phosphate, aspartate, bicarbonate and gluconate are also used.[1] Labels show the amount of potassium itself (elemental potassium), not the weight of the whole salt.[1] Most US potassium supplements contain up to 99 mg per serving, and multivitamins with potassium about 80 mg.[1]

How long

The blood pressure trials in a 2017 review lasted 4 to 15 weeks.[1] The kidney stone trials in a 2015 Cochrane review lasted at least 6 months, and one placebo-controlled trial lasted 3 years.[5][10]

Upper limit

Neither the US nor the EU has set an upper limit for potassium.[1][8] EFSA noted that about 3,000 mg a day as potassium chloride supplements, on top of food, caused no adverse effects in healthy adults over the long term. Case reports linked 5,000 to 7,000 mg a day from supplements to effects on the heart.[8] People with kidney disease, or who take medicines that keep potassium in the body, can get too much even from food. They should ask a doctor or pharmacist first.[1]

Doses in studies

Most studies gave 50 to 100 mmol a day, for 1 to 4 weeks.

The counts are study groups. A study group is one set of people in a study who took the same dose. One study can have several groups. These are amounts from studies, not advice for you.

How much a day59 groups in 43 studies
  1. Up to 10 mmol2 groups
  2. 10 to 25 mmol8 groups
  3. 25 to 50 mmol11 groups
  4. 50 to 100 mmol35 groups
  5. 100 to 250 mmol3 groups
For how long101 groups in 73 studies
  1. 1 week or less27 groups
  2. 1 to 4 weeks35 groups
  3. 1 to 3 months21 groups
  4. 3 to 6 months10 groups
  5. 6 to 12 months3 groups
  6. More than a year5 groups
Half of the groups took less than 60 mmol a day. Half took more.Half of the groups took 39 to 85 mmol a day. A quarter took less, a quarter took more.

Taken together

27 of 104 study groups took potassium with something else. This shows what studies gave together, not what works together.

  1. Calcium6 studies10
  2. Magnesium8 studies8
  3. Electrolytes3 studies5
Bars and numbers count study groups. A companion is shown only when at least 3 different studies gave it.

Protocols

What studies used when they gave potassium for one goal, or to a group of people.

Each protocol describes what studies used, for one goal or for one group of people. It is not advice for you: talk to a doctor before you start a supplement.

Questions

12 questions in 4 groups. Open one for the short answer; each has its own page with the full answer and sources.

Basics
Which foods contain potassium?

Many fruits and vegetables, some beans and other legumes, and potatoes are rich sources. Milk, yogurt, meat, poultry, fish and nuts also contain potassium.[1] Some examples per serving:

  • dried apricots, half a cup: 755 mg[1]
  • lentils, cooked, 1 cup: 731 mg[1]
  • potato, baked, flesh only, 1 medium: 610 mg[1]
  • kidney beans, canned, 1 cup: 607 mg[1]
  • orange juice, 1 cup: 496 mg[1]
  • banana, 1 medium: 422 mg[1]
  • milk, 1% fat, 1 cup: 366 mg[1]
  • salmon, Atlantic, farmed, cooked, 3 ounces: 326 mg[1]
  • white rice, cooked, 1 cup: 54 mg[1]

The body absorbs about 85 to 90% of the potassium in food.[1] US adults get the most from milk, coffee, tea, other drinks without alcohol, and potatoes.[1]

Open the answer with sources ›
What happens if you do not get enough potassium?

A low intake can raise blood pressure, the risk of kidney stones, bone turnover and calcium loss in urine.[1] A low blood level (hypokalemia, below about 3.6 mmol/L) is rare in healthy people with normal kidneys. It affects up to 21% of people in hospital, usually because of diuretics and other medicines.[1]

  • Mild hypokalemia causes constipation, tiredness, muscle weakness and a general feeling of being unwell.[1]
  • Below about 2.5 mmol/L it can cause large amounts of urine, poor glucose control, paralysis, weak breathing and abnormal heart rhythms.[1]

Low food intake alone rarely causes hypokalemia. It can result from diarrhea, vomiting, refeeding after starvation, laxative abuse, diuretics, heavy sweating, dialysis and eating clay.[1] Low magnesium increases potassium loss in urine. More than half of people with clinically significant hypokalemia might also lack magnesium.[1]

Open the answer with sources ›
Why do potassium supplements contain only 99 mg?

Many US makers limit potassium supplements to 99 mg per serving because of rules for potassium medicines.[1] 99 mg is about 2% of the US Daily Value of 4,700 mg.[1] There are two reasons:

  • The FDA ruled that some potassium chloride medicines with more than 99 mg are not safe, because they were linked to injuries of the small bowel.[1]
  • The FDA requires a warning on some potassium salts with more than 99 mg per tablet.[1]

The FDA has not ruled whether supplements above 99 mg need such a warning.[1] In the US, 12% of people take a supplement with potassium, and it adds only 87 mg a day on average.[1] For comparison, one medium banana has 422 mg.[1]

Open the answer with sources ›
Benefits
Does potassium lower blood pressure?

Yes, in people with high blood pressure, by a few mmHg. A 2017 review of 25 trials found 4.48 mmHg lower systolic and 2.96 mmHg lower diastolic pressure.[2][1] In people with normal blood pressure, reviews found no clear effect.[3][1]

Read the full answer ›
Do salt substitutes with potassium lower the risk of stroke?

In one large trial, yes. The trial followed 20,995 people in rural China who had had a stroke, or were 60 or older with high blood pressure. A salt with 25% potassium chloride lowered their stroke rate by 14% over about 4.7 years.[13] A 2022 Cochrane review rates the effect on non-fatal stroke and cardiovascular deaths as slight, with moderate certainty.[4]

Read the full answer ›
Does potassium citrate prevent kidney stones?

In people who already had calcium stones, yes. In a 2015 Cochrane review of 7 trials with 477 people, citrate salts cut the risk of new stones to about a quarter (risk ratio 0.26).[5] The citrate, not the potassium, is thought to prevent the stones.[1]

Read the full answer ›
Does potassium help bones?

Potassium citrate and bicarbonate lower calcium loss in urine, but have not clearly raised bone density. In a 2015 review of 14 studies, potassium citrate and potassium bicarbonate lowered calcium and acid in urine and a marker of bone breakdown (NTX). They did not change bone density.[6] Single trials disagree. In 201 healthy adults over 65, 60 mEq of potassium citrate a day for 2 years raised spine density by 1.7% more than placebo. It also lowered a predicted fracture risk score (FRAX). Both groups also took calcium and vitamin D.[11] In 276 women aged 55 to 65, 2 years of potassium citrate did not change bone turnover or density.[14]

Open the answer with sources ›
Does potassium help heart rhythm?

A low blood level can cause abnormal heart rhythms, especially in people with heart disease.[1] A 2025 trial included 1,200 people with an implanted defibrillator (ICD) and a potassium level of 4.3 mmol/L or less. Half were treated to reach 4.5 to 5.0 mmol/L with potassium supplements, a medicine (a mineralocorticoid receptor antagonist) or both, plus advice on diet. Over a median of 39.6 months, 22.7% had a dangerous heart rhythm, an unplanned hospital stay for arrhythmia or heart failure, or died, against 29.2% with standard care.[15] In a 2024 trial of 1,690 people after heart bypass surgery, giving potassium only below 3.6 mEq/L was not worse than keeping it at 4.5 mEq/L or more. Atrial fibrillation occurred in 27.8% with the lower threshold and 26.2% with the higher one.[16] Both trials were in heart patients under medical care, not in healthy people taking a supplement.[15][16]

Open the answer with sources ›
Does potassium help with muscle cramps?

A 2026 review of 9 studies with 11,274 people looked for causes of cramps during exercise. People with cramps had higher, not lower, blood potassium after a race (moderate evidence), and hydration showed no consistent link.[7] The strongest risk factor was earlier cramps, with about 4.4 times higher odds.[7] A low blood potassium level can cause muscle weakness, and a very low level paralysis.[1]

Open the answer with sources ›
Does potassium lower blood sugar?

The evidence is early. Observational studies link a lower potassium intake or blood level with higher fasting glucose, insulin resistance and type 2 diabetes.[1] In a pilot trial of 29 African American adults with prediabetes, 40 mEq (1,564 mg) of potassium chloride a day for 3 months kept fasting glucose stable. It changed by -1.1 mg/dL, against +6.1 mg/dL with placebo, but glucose tolerance test results did not differ.[17][1] NIH says that more trials are needed before the link can be confirmed.[1]

Open the answer with sources ›
Safety
Can too much potassium be dangerous?

Yes, when the kidneys cannot remove it. Healthy kidneys pass extra potassium into urine, so food does not raise the blood level too high.[1] Kidney disease and some blood pressure medicines can cause high blood potassium (hyperkalemia), even at normal food intakes.[1]

Read the full answer ›
Forms and timing
Is potassium citrate better than potassium chloride?

It depends on the aim, and few studies compare them. Blood pressure trials mostly used potassium chloride.[1] Kidney stone trials used potassium citrate and other citrate salts, because the citrate is thought to prevent the stones.[1][5] For bones, potassium citrate and bicarbonate lowered calcium in urine more than potassium chloride did.[6] A trial treated 42 patients who had a low blood level with 80 mmol a day of potassium chloride, or of potassium citrate and bicarbonate. Both raised the level equally, from 3.2 to about 4.0 mmol/L within 4 to 6 days.[18] The body absorbs about 94% of potassium gluconate, as much as from potatoes.[1][9] Liquid potassium chloride is absorbed within a few hours. Enteric-coated tablets, which dissolve in the small intestine and not in the stomach, are absorbed more slowly.[1] Labels list the amount of potassium itself, not of the whole salt.[1]

Open the answer with sources ›

References

  1. Potassium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  2. The effect of potassium supplementation on blood pressure in hypertensive subjects: A systematic review and meta-analysis. Filippini T, Violi F, D'Amico R, Vinceti M Int J Cardiol, 2017. PMID 28024910
  3. Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. Aburto NJ, Hanson S, Gutierrez H, Hooper L, Elliott P, Cappuccio FP BMJ, 2013. PMID 23558164
  4. Replacing salt with low-sodium salt substitutes (LSSS) for cardiovascular health in adults, children and pregnant women. Brand A, Visser ME, Schoonees A, Naude CE Cochrane Database Syst Rev, 2022. PMID 35944931
  5. Citrate salts for preventing and treating calcium containing kidney stones in adults. Phillips R, Hanchanale VS, Myatt A, Somani B, Nabi G, Biyani CS Cochrane Database Syst Rev, 2015. PMID 26439475
  6. The effect of supplementation with alkaline potassium salts on bone metabolism: a meta-analysis. Lambert H, Frassetto L, Moore JB, Torgerson D, Gannon R, Burckhardt P, et al. Osteoporos Int, 2015. PMID 25572045

Review history

  1. 9 Nov 2026CheckedReviewerChecked every claim against its source.
  2. 9 Nov 2026Page createdResearcherFirst edition, written from PubMed and public health sources.