Type the potassium number on your label and say what it is. You get the potassium itself, the whole compound and mEq, and where a day of it sits against the Daily Value and the adequate intake — with the reason most bottles stop at 99 mg. It never tells you how many to take.
Your label, in a day
99 mg of potassium a day 2.1% of the 4,700 mg Daily Value · 3.8% of the 2,600 mg adequate intake for a woman 19+
The bar is the adequate intake; the fill is what the label gives.
99 mg potassium a serving = 593 mg of potassium gluconate = 2.5 mEq
This is not medical advice. Potassium is the supplement where kidney disease and some blood-pressure medicines change everything — ask your doctor or pharmacist before you take any.
Most potassium supplements hold 99 mg — about 2% of the 4,700 mg Daily Value — and NIH’s Office of Dietary Supplements says why: “Many dietary supplement manufacturers and distributors limit the amount of potassium in their products to 99 mg (which is only about 2% of the DV) because of two concerns related to potassium-containing drugs.” A medium banana holds 422 mg.
How to use it
Type the potassium number from your label and say what it is. On a Supplement Facts panel it is the potassium itself — ODS: “The Supplement Facts panel on a dietary supplement label declares the amount of elemental potassium in the product, not the weight of the entire potassium-containing compound.” If you only have the compound’s weight (595 mg potassium gluconate), pick “mg compound”; if it is a prescription written in mEq, pick mEq. Add the form, how many servings a day and who takes it. You get the potassium a serving and a day, the compound and mEq, and where a day sits against the Daily Value and the adequate intake. It never says how many to take.
Why 99 mg
ODS gives two FDA reasons, both about potassium drugs: “First, FDA has ruled that some oral drug products that contain potassium chloride and provide more than 99 mg potassium are not safe because they have been associated with small-bowel lesions”, and “Second, FDA requires some potassium salts containing more than 99 mg potassium per tablet to be labeled with a warning about the reports of small-bowel lesions”. So “Potassium-only supplements are also available, and most contain up to 99 mg potassium.” The result is that supplements barely move a day’s intake: in national survey data, “supplement use adds a mean of only 87 mg to total daily potassium intakes”.
How much of each form is potassium
ODS lists the forms: “In dietary supplements, potassium is often present as potassium chloride, but many other forms—including potassium citrate, phosphate, aspartate, bicarbonate, and gluconate—are also used”. The share that is potassium follows from each compound’s formula and the atomic weights. Phosphate and aspartate are left out here: each is sold as several different salts, so one percentage would not be honest.
| Form | Formula | Potassium | Compound for 99 mg |
|---|---|---|---|
| Potassium gluconate | C6H11KO7 | 16.7% | 593 mg |
| Potassium chloride | KCl | 52.4% | 189 mg |
| Potassium citrate (monohydrate) | K3C6H5O7·H2O | 36.2% | 274 mg |
| Potassium bicarbonate | KHCO3 | 39.1% | 253 mg |
That is why a “potassium gluconate 595 mg” tablet and a “99 mg potassium” tablet are the same tablet. On absorption, ODS reports that “humans absorb about 94% of potassium gluconate in supplements, and this absorption rate is similar to that of potassium from potatoes”.
The adequate intake, and food beside it
There is no RDA for potassium, only an adequate intake (AI), and no upper limit: “Therefore, the committee did not set a UL for potassium.” The Daily Value on labels is one number — “The DV for potassium is 4,700 mg for adults and children age 4 years and older”.
| Who | Adequate intake | One 99 mg serving |
|---|---|---|
| Woman 19+ | 2,600 mg | 3.8% |
| Man 19+ | 3,400 mg | 2.9% |
| Pregnant, 19+ | 2,900 mg | 3.4% |
| Breastfeeding, 19+ | 2,800 mg | 3.5% |
| Girl 14–18 | 2,300 mg | 4.3% |
| Boy 14–18 | 3,000 mg | 3.3% |
| Child 4–8 | 2,300 mg | 4.3% |
From ODS’s food table: a medium banana 422 mg, a baked potato 610 mg, a cup of cooked lentils 731 mg, half a cup of dried apricots 755 mg, a cup of brewed coffee 116 mg.
Worked examples
- 99 mg potassium, once a day, a woman: 2.1% of the Daily Value and 3.8% of her 2,600 mg adequate intake. A medium banana holds 4.3 times as much.
- 595 mg potassium gluconate: 99 mg of potassium — the same tablet, labelled by its compound.
- 10 mg potassium chloride on a fat burner’s label (“Potassium (as Potassium Chloride) – 10 mg”): 10 mg of potassium, 0.2% of the Daily Value.
- A 10 mEq prescription tablet: 391 mg of potassium, by ODS’s 39.1 mg per mEq — four times the supplement cap, and a dose your doctor sets.
Who should not take potassium on their own
ODS is specific: “However, in people with impaired urinary potassium excretion due to chronic kidney disease or the use of certain medications, such as angiotensin converting enzyme (ACE) inhibitors or potassium-sparing diuretics, even dietary potassium intakes below the AI can cause hyperkalemia”. And: “Individuals at risk of hyperkalemia should consult a physician or registered dietitian about appropriate potassium intakes from all sources.” Even without a UL, “very high amounts of potassium supplements or salt substitutes that contain potassium could exceed the kidney’s capacity to excrete potassium, causing acute hyperkalemia even in healthy individuals.”
Common mistakes
- Reading the compound as the potassium. 595 mg on the front of a gluconate bottle is 99 mg of potassium.
- Expecting a 99 mg tablet to make up a shortfall. It is about 4% of a woman’s adequate intake; food carries potassium in hundreds of milligrams.
- Forgetting salt substitutes. ODS: they hold “from about 440 mg to 2,800 mg potassium per teaspoon”.
- Adding potassium alongside a blood-pressure or kidney medicine without asking. That is exactly the group ODS warns about.
Frequently asked questions
Why do potassium supplements only have 99 mg?
Because of FDA rules on potassium drugs. ODS: manufacturers “limit the amount of potassium in their products to 99 mg (which is only about 2% of the DV) because of two concerns related to potassium-containing drugs” — FDA found some potassium chloride drugs over 99 mg unsafe (small-bowel lesions) and requires a warning on some potassium salts above 99 mg a tablet.
Potassium citrate vs potassium gluconate: what is the difference?
How much of the compound is potassium: citrate (as the monohydrate) is 36.2% potassium, gluconate 16.7%, so 99 mg of potassium takes 274 mg of citrate or 593 mg of gluconate. A Supplement Facts panel prints the potassium itself, so two “99 mg” labels hold the same potassium.
Potassium gluconate vs potassium chloride?
Chloride is 52.4% potassium, gluconate 16.7%. Chloride is the form in salt substitutes and most prescription potassium; ODS reports that humans absorb about 94% of potassium gluconate from supplements, similar to potassium from potatoes.
How much potassium do I need a day?
The adequate intake is 2,600 mg for women 19 and over and 3,400 mg for men, 2,900 mg in pregnancy and 2,800 mg while breastfeeding. The Daily Value on labels is 4,700 mg. The Vitamin & Mineral Dose Lookup has every age group.
Is there an upper limit for potassium?
No. ODS: “the committee did not set a UL for potassium”, because the case reports were not sufficient evidence. But with kidney disease, ACE inhibitors or potassium-sparing diuretics, “even dietary potassium intakes below the AI can cause hyperkalemia” — ask your doctor before any supplement.
How many mg is 1 mEq of potassium?
39.1 mg. ODS: “1 mmol = 1 milliequivalent [mEq] or 39.1 mg potassium”. So a 10 mEq tablet is 391 mg and a 20 mEq tablet 782 mg — prescription amounts, set by your doctor.
Read next
- Multivitamins for adults: how to choose the right complex
- Best fat burner supplements — one of them lists 10 mg of potassium chloride.
- 20 best brain foods for vegetarians — bananas and their potassium.
- Brain food: 52 foods for mood and cognition
- The Mineral Form Finder — the same arithmetic for iron, zinc and calcium.
This is not medical advice, and nothing here diagnoses or treats anything. Potassium with kidney disease or with blood-pressure medicines (ACE inhibitors, ARBs, potassium-sparing diuretics) is a conversation with your doctor or pharmacist first. Some links on this site are affiliate links: I buy what I review at full price, and a commission never changes a verdict.