Potassium

mineralpotassium atom

What is it

Potassium is an essential mineral and major intracellular electrolyte. It is critical for nerve transmission, muscle contraction (including the heartbeat), blood pressure regulation, and maintaining fluid balance.

How it works

Potassium is the main cation inside cells, while sodium dominates extracellular fluid. The sodium-potassium pump actively maintains this gradient, using a significant portion of the body's resting energy expenditure. The gradient enables nerve signals, muscle contraction, and many transport processes. The kidneys regulate body potassium tightly by adjusting urinary excretion. The body cannot store potassium effectively, so daily intake matters. High-potassium diets reduce blood pressure by promoting sodium excretion and through direct vasodilation. Most adults consume far below the recommended intake.

Evidence for 5 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Blood pressure reduction

Grade A

Strong evidence

Increasing dietary potassium reduces blood pressure, with stronger effects in people with hypertension and those with high sodium intake. Recommended by hypertension guidelines.

Stroke prevention

Grade B

Good evidence

Observational and randomized data link higher potassium intake to reduced stroke risk, likely through blood pressure and direct vascular effects.

Kidney stone prevention

Grade B

Good evidence

Potassium citrate (prescription) reduces calcium oxalate and uric acid stone formation by alkalinizing urine.

Bone health

Grade C

Moderate evidence

Higher potassium intake (especially from fruits and vegetables) is associated with better bone density, possibly by reducing acid load on the skeleton.

Muscle cramps

Grade C

Moderate evidence

Cramps related to potassium loss respond to replacement. Most ordinary exercise cramps are not from potassium deficiency.

3 commercial forms

Potassium chloride (KCl)

well absorbed, standard prescription form

Standard prescription form used to replace deficits caused by diuretics. Causes stomach upset; extended-release formulations are gentler.

Potassium citrate

alkalinizing, prevents kidney stones

Prescription form used for kidney stone prevention because it alkalinizes urine and binds calcium.

Potassium gluconate

common in OTC supplements (99 mg)

The form in most over-the-counter potassium supplements, limited to 99 mg per dose by the FDA.

Dosage

The Adequate Intake (AI) is 3,400 mg per day for adult men and 2,600 mg for women. Most adults consume only 50 to 75 percent of this. Supplements are restricted by FDA to 99 mg per dose to prevent accidental overdose — this is much less than dietary intake. Higher doses require prescription.

When and how to take it

Dietary potassium from food can be eaten any time. The kidneys efficiently distribute and excrete potassium so dose timing matters less than total daily intake. Spread potassium-rich foods across meals rather than consuming a huge dose at once. Prescription potassium chloride is usually divided into multiple daily doses with meals.

Food sources

Food	Amount	%DV
Potato (baked, with skin), 1 medium	926 mg	20%
Banana, 1 medium	422 mg	9%
Sweet potato (baked, with skin)	542 mg	12%
Beans (kidney, canned), 1/2 cup	353 mg	8%
Salmon, 3 oz cooked	475 mg	10%
Avocado, 1/2 fruit	487 mg	10%
Spinach (cooked), 1/2 cup	419 mg	9%
Tomato juice, 1 cup	527 mg	11%
Yogurt (plain), 1 cup	380 mg	8%
Coconut water, 1 cup	404 mg	9%

Safety

Hyperkalemia (high blood potassium) is dangerous and can cause fatal heart rhythm abnormalities. It is most likely in people with kidney disease, those on potassium-sparing diuretics, ACE inhibitors, or ARBs, and those with Addison's disease. For healthy adults eating food-source potassium, hyperkalemia is rare. Dietary potassium from fruits, vegetables, and other foods is safe. Salt substitutes (which are often potassium chloride) can deliver substantial potassium quickly and may cause hyperkalemia in susceptible people.

Who should be cautious

People with chronic kidney disease should not take potassium supplements or use salt substitutes without medical guidance. Those on ACE inhibitors, ARBs, or potassium-sparing diuretics should avoid potassium supplements unless prescribed. Older adults are at higher risk of medication-related hyperkalemia.

Interactions

ACE inhibitors, ARBs, and potassium-sparing diuretics (spironolactone, amiloride) raise potassium and can cause dangerous accumulation with supplements. NSAIDs also raise potassium. Loop and thiazide diuretics lower potassium and may necessitate replacement under medical guidance. Digoxin toxicity is affected by potassium levels.

Frequently asked questions

Why are over-the-counter potassium supplements limited to 99 mg?⌄

To prevent accidental hyperkalemia. Higher doses require prescription because they can cause dangerous heart rhythm problems.

Can I get enough potassium from food?⌄

Yes, but most Americans do not. Potatoes, beans, leafy greens, fruit, fish, and dairy are good sources. Aim for several servings of high-potassium foods daily.

Should I use a salt substitute?⌄

It can help reduce sodium and increase potassium, but talk to your doctor first if you have kidney disease or take medications that raise potassium.

Do bananas have enough potassium for muscle cramps?⌄

Bananas provide moderate potassium (about 422 mg). Most exercise-related cramps are not caused by potassium deficiency. Potatoes, beans, and yogurt have more.

Can potassium help my blood pressure?⌄

Yes. Higher dietary potassium, especially from food, reliably lowers blood pressure, particularly in people with hypertension.

Track Potassium with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

Coming to App Store

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.