Quick answer
There is no set supplement dose. Adults need 2,600 mg (women) to 3,400 mg (men) of potassium a day from all sources, and over-the-counter supplements usually hold up to 99 mg per serving. Potassium medicines with 100 mg or more per tablet are prescription drugs, dosed by a doctor against blood tests.1,2,3
Key facts
- One mEq of potassium is 39.1 mg, the conversion behind prescription labels.1
- The Daily Value on labels is 4,700 mg, so a 99 mg serving shows as about 2%.1
- Multivitamins that contain potassium typically provide about 80 mg.1
- Prescription potassium chloride is given so that no single dose is larger than 20 mEq.3
How much you need by age
| Who | Milligrams a day |
|---|---|
| Adult men | 3,400 |
| Adult women | 2,600 |
| Pregnant adults | 2,900 |
| Breastfeeding adults | 2,800 |
| Teen boys, 14 to 18 | 3,000 |
| Teen girls, 14 to 18 | 2,300 |
| Pregnant teens | 2,600 |
| Breastfeeding teens | 2,500 |
| Boys 9 to 13 | 2,500 |
| Girls 9 to 13 | 2,300 |
| Children 4 to 8 | 2,300 |
| Children 1 to 3 | 2,000 |
A committee of the National Academies updated these adequate intakes in 2019, and they stay the same at 51 and older. NIH notes that most people in the US fall short of them even when supplements are counted.1,4
Reading a potassium label
Supplement Facts panels list the amount of potassium itself, not the weight of the whole compound. Potassium iodide on a label is there as a source of iodine, in microgram amounts, not as a source of potassium.1
Prescription labels give potassium in milliequivalents, or mEq. One mEq is 39.1 mg, so a 10 mEq tablet carries about 391 mg of potassium and a 20 mEq tablet about 782 mg.1,3
What a 99 mg serving covers
Most potassium-only products hold up to 99 mg per serving, and multivitamins with potassium about 80 mg. Against adequate intakes of 2,600 to 3,400 mg, a 99 mg serving covers roughly 3% to 4% of the day's need.1
The kidneys pass at least about 195 mg of potassium a day in urine, so the body cannot stay in balance on less than about 400 to 800 mg a day.1
The shortfall is usually a few hundred milligrams. US women average about 280 mg below their adequate intake from food, and men about 384 mg below theirs. One medium banana (422 mg) or baked potato (610 mg) would cover either gap, and a 99 mg tablet would not.1
Prescription potassium, and why supplements stop at 99 mg
Potassium chloride tablets for low blood potassium (hypokalemia) are prescription medicines. Their label gives 20 mEq a day, about 782 mg, as a typical amount for prevention, and 40 to 100 mEq a day, about 1,564 to 3,910 mg, in divided doses to correct a shortfall, with no more than 20 mEq at once and blood potassium checked along the way.1,3
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.1,2
Do not copy prescription amounts with over-the-counter products or salt substitutes. NIH says very large amounts can overwhelm what the kidneys can clear, even in healthy people.1
Amounts used in research
In clinical trials, potassium supplements were given at about 782 to 4,692 mg a day (20 to 120 mmol), mostly as potassium chloride, for 1 to 36 months.1
Many of these trials were in adults with high blood pressure, and their amounts are not a guide for dosing yourself. Several common blood pressure medicines raise potassium on their own, which is one more reason to ask first.1,4
Who needs a doctor to set the amount
- People with kidney disease or reduced kidney function1
- People taking an ACE inhibitor, an ARB, or a potassium-sparing diuretic such as spironolactone, amiloride or triamterene3,4
- People taking a loop or thiazide diuretic, who may need potassium but should get the amount from their prescriber1,5
- People with type 1 diabetes, heart failure, liver disease or adrenal insufficiency1
Questions people ask
How much potassium should a woman take?
Women need about 2,600 mg a day from all sources, 2,900 mg in pregnancy and 2,800 mg while breastfeeding. US women average about 2,320 mg from food, so the typical gap is about 280 mg, less than a medium banana provides.1
How much potassium should a man take?
Men need about 3,400 mg a day from all sources. US men average about 3,016 mg from food, about 384 mg short, a little less than the 422 mg in a medium banana.1
Should I take potassium for leg cramps?
Ask your doctor rather than dosing yourself. Mildly low blood potassium can cause muscle weakness, tiredness and constipation, and it usually comes from medicines such as diuretics or from vomiting or diarrhea, not from diet. A blood test can show whether your potassium is low.1,4
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Sources
- National Institutes of Health, Office of Dietary Supplements. Potassium: Fact Sheet for Health Professionals. Updated June 2, 2022. Opened 2026-10-07.
- 21 CFR 201.306. Potassium salt preparations intended for oral ingestion by man. Electronic Code of Federal Regulations, current as of October 1, 2026. Opened 2026-10-07.
- Potassium chloride extended-release tablets: prescribing information (Upsher-Smith Laboratories). DailyMed, U.S. National Library of Medicine. Published July 28, 2026. Opened 2026-10-07.
- Office of Dietary Supplements, National Institutes of Health. Potassium: Fact Sheet for Consumers. Updated March 22, 2021. Opened 2026-10-07.
- Hydrochlorothiazide capsules: prescribing information (Westminster Pharmaceuticals). DailyMed, U.S. National Library of Medicine. Published October 1, 2026. Opened 2026-10-07.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.