Potassium chloride is 52.4 percent potassium by weight and potassium citrate 38.3 percent, so 500 mg of potassium takes just under 1 gram of chloride or about 1.3 to 1.4 grams of citrate. The form changes that weight, the taste and how well the salt dissolves. Whether the partner molecule matters for anything else is not settled: the randomized trials that compared the salts are small and point in different directions. For how much potassium adults need and what ordinary food supplies, see what the 3,400 mg daily potassium target looks like in food.
Written by Dr Brad Stanfield, a general practitioner registered in New Zealand and Australia. Check every number against the sources at the end. This is general information, not medical advice.
The short version
- Once a potassium salt dissolves, the potassium is the same potassium ion whichever salt it came from. The partner molecule sets the taste, how easily the salt dissolves and how much potassium each gram carries.
- The forms differ enormously in potassium by weight, from 52.4 percent for potassium chloride down to 16.7 percent for potassium gluconate. That is the most useful thing to know when reading a label.
- At least seven small randomized trials have compared potassium salts with one another. Their results point in different directions, and none is large or long enough to settle it. We use citrate for taste and solubility.
- Potassium citrate has one chemical property potassium chloride lacks: after it is absorbed, the citrate is metabolized to bicarbonate, an alkali, and less than 5 percent of it leaves in the urine unchanged.
- The front of a potassium pack often gives the weight of the whole salt, while the Supplement Facts panel gives the potassium itself: 595 mg of potassium gluconate holds 99 mg of potassium.
A potassium label is describing a salt, not potassium
Potassium is a soft metal that reacts violently with water, so it never sits in a bottle on its own. It always arrives bonded to a partner as a salt. Potassium chloride is potassium plus chloride, the same chloride in table salt. Potassium citrate is potassium plus citrate, the ion that makes lemons sour.
Two different numbers get printed on labels and they are not the same. One is the weight of the whole salt. The other is the potassium inside it, which labels call elemental potassium.
The gap is large. Here is the potassium in each of the salts you will actually meet.
Work an example. A common potassium tablet in the United States says 595 mg potassium gluconate on the front and 99 mg potassium on the back. Potassium gluconate has a molecular weight of 234.25, of which potassium is 39.10, or 16.7 percent. Multiply 595 by 0.167 and you get 99. The other 496 mg is gluconate.
Why 99 and not a round 100? Two United States drug rules draw their line at 100 mg of potassium per tablet: one requires a warning about small-bowel injury, and the other lists some potassium chloride tablets among drug products withdrawn from the market. Most potassium-only supplements stay at or below 99 mg, one milligram under that line, and why potassium pills stop at 99 mg sets out what each rule covers.
The six forms, side by side
| Form and potassium by weight | In water and taste | What the evidence supports |
|---|---|---|
| Potassium citrate. 38.3% dry, 36.2% as the monohydrate | The most soluble of the group. Saline, mildly tart | Same potassium as the others. Converted to bicarbonate, an alkali, after absorption |
| Potassium chloride. 52.4% | 35.5 g per 100 g of water at 25 °C. Bitter and metallic | Used in most potassium trials, so it has the largest evidence base |
| Potassium bicarbonate. 39.1% | Freely soluble. Soapy, fizzes with acid | Matched the chloride on most measures in a 2010 trial comparing the two |
| Potassium gluconate. 16.7% | Freely soluble. Mild, slightly sweet | Absorbed above 94%, same as potassium from potatoes. No advantage beyond taste |
| Potassium aspartate. About 22.8% | Soluble. Faintly bitter | We found no trial comparing it with another potassium salt |
| Potassium from food. Varies; a medium baked potato, about 925 mg | Already in solution. Tastes like food | Absorbed as well as a supplement, and arrives with everything else in the plant |
-
Potassium citrate. 38.3% dry, 36.2% as the monohydrate
- In water and taste
- The most soluble of the group. Saline, mildly tart
- What the evidence supports
- Same potassium as the others. Converted to bicarbonate, an alkali, after absorption
-
Potassium chloride. 52.4%
- In water and taste
- 35.5 g per 100 g of water at 25 °C. Bitter and metallic
- What the evidence supports
- Used in most potassium trials, so it has the largest evidence base
-
Potassium bicarbonate. 39.1%
- In water and taste
- Freely soluble. Soapy, fizzes with acid
- What the evidence supports
- Matched the chloride on most measures in a 2010 trial comparing the two
-
Potassium gluconate. 16.7%
- In water and taste
- Freely soluble. Mild, slightly sweet
- What the evidence supports
- Absorbed above 94%, same as potassium from potatoes. No advantage beyond taste
-
Potassium aspartate. About 22.8%
- In water and taste
- Soluble. Faintly bitter
- What the evidence supports
- We found no trial comparing it with another potassium salt
-
Potassium from food. Varies; a medium baked potato, about 925 mg
- In water and taste
- Already in solution. Tastes like food
- What the evidence supports
- Absorbed as well as a supplement, and arrives with everything else in the plant
The forms, one at a time
Potassium citrate
Potassium citrate is the potassium salt of citric acid, the acid in citrus fruit. Pharmacies and food manufacturers use the monohydrate at 36.2 percent potassium; the dry salt is 38.3 percent. Either way, 500 mg of potassium takes about 1.3 to 1.4 grams of it. It is the most soluble of the common potassium salts by a wide margin, so it vanishes into a drink instead of drifting to the bottom of the glass, and it reads saline and slightly tart rather than bitter. It has been a food additive for decades, carrying the European additive number E332.
Potassium chloride
Potassium chloride is potassium bonded to chloride, the same chloride in table salt. It carries more potassium per gram than anything else here at 52.4 percent, and it is cheap, which is why it sits inside low sodium salt substitutes and most prescription potassium.
Its problem is the taste. A 2012 sensory study in the Journal of Food Science had panelists describe potassium chloride solutions, and the words that came back were bitter and metallic, with "chemical" alongside them. Adding sodium chloride reduced those side tastes, which is why salt substitutes are blends rather than pure potassium chloride.
Potassium bicarbonate
Potassium bicarbonate is potassium bonded to bicarbonate, the buffer the blood already runs on. At 39.1 percent potassium it is freely soluble, and it delivers alkali directly rather than being metabolized into it. It also fizzes on contact with acid, useful in an effervescent tablet and a nuisance in a still drink. In a 2010 randomized trial of 42 adults that set it against potassium chloride for four weeks each, the two salts could not be told apart on most of what was measured; they differed in what happened to calcium and albumin in the urine.
Potassium gluconate
Potassium gluconate is potassium bonded to gluconate, a mild sugar acid. It is the gentlest tasting of the salts, which is why it dominates the 99 mg tablet shelf, and the least dense at 16.7 percent, so 500 mg of potassium would take about 3 grams of powder.
It is also the form with the best absorption data. In a 2016 randomized crossover trial, 35 healthy adults took potassium as gluconate supplements or as unfried potato at matched doses. The rise in serum potassium did not differ by source, and absorption was above 94 percent across every arm. That is the cleanest evidence that absorption is not a problem any form needs to solve, which makes "highly absorbable form" a weak thing to pay extra for.
Potassium aspartate
Potassium aspartate is potassium bonded to aspartic acid, an amino acid. At roughly 22.8 percent potassium by weight, it is usually sold on the idea that an amino acid carrier gets minerals into cells more effectively. The trial that would test that against another potassium salt does not appear to exist, and with gluconate already absorbed above 94 percent, there is not much of a gap for a carrier to close.
Potassium from food
Potassium in food is not a single salt, and it is not chloride. That was the reason He and colleagues ran their 2005 trial at all: most potassium trials before it had used potassium chloride, while the potassium in fruit and vegetables is not a chloride salt. A medium baked potato with the skin on carries about 925 mg, and the 2016 trial found the potassium in potatoes was absorbed as well as the potassium in a supplement. More on how much potassium ordinary food portions carry.
Has any trial settled which potassium salt is better?
No. At least seven small randomized trials have compared potassium salts with one another in people. The seven listed in the sources below each set potassium chloride against potassium citrate or potassium bicarbonate, studied between 11 and 85 people, and gave each salt for anything from a single dose to eight weeks. They measured different things, among them blood pressure, how the body handled blood sugar and how the kidneys dealt with the extra potassium. Their results point in different directions. In some the salts could not be told apart; in others one salt changed a measurement that the other did not, and which salt that was changed from trial to trial. None is large or long enough to settle whether the partner molecule matters.
So this article makes no claim for citrate over chloride. Potassium Fiber uses citrate for taste and solubility, for the reasons set out further down.
The one thing citrate does that chloride does not
Potassium citrate gets metabolized. Potassium chloride does not.
After potassium citrate is absorbed, the citrate is metabolized to bicarbonate, an alkali, and less than 5 percent of it leaves in the urine unchanged, according to the National Library of Medicine's PubChem record for potassium citrate. Chloride is not metabolized, so potassium chloride delivers the same potassium without that alkali.
That conversion is the one chemical difference between the two salts once they are absorbed. Whether it matters for anything is the question the trials comparing the salts have not settled, and we make no claim on the strength of it.
Why this drink uses potassium citrate, and why 500 mg
If no trial has shown one potassium salt beating another, why pick citrate at all? Because the drink has to be drinkable.
Taste. Citrate reads saline and slightly tart. Chloride reads bitter and metallic. In something you are meant to drink every day, that decides whether the pouch gets finished or abandoned at the back of a cupboard.
Solubility. Citrate is the most soluble of these salts, so it disappears rather than settling. The drink already carries 8 grams of fiber from acacia gum, the dried sap of the acacia tree, and anything gritty on top is a problem.
Weight. At 36 to 38 percent potassium, 500 mg needs about 1.3 to 1.4 grams of citrate. Gluconate would need 3 grams for the same potassium, a lot of powder to spend on a carrier.
Regulatory simplicity. In Australia, a potassium chloride medicine taken by mouth at 550 mg or more per dosage unit, such as a tablet, is prescription-only under the Poisons Standard. Potassium citrate does not appear in the standard at all.
Then the dose. The adult Adequate Intake set by the National Academies is 3,400 mg a day for men and 2,600 mg for women, so a 500 mg serving is about 15 to 19 percent of it: a real share of a day's potassium, and not a treatment for anything.
Going to 1,000 mg a serving would buy a bigger number on the front of the pouch and cost twice over. It doubles the salt load to roughly 2.6 grams, which is much harder to mask in the same glass of water.
There is a tempting argument that pairing potassium with 8 grams of fiber lets us push the potassium higher, because the fiber cushions it. We found no trial showing that. Fermentable fiber produces gas (more on why fiber causes gas and bloating), and the Office of Dietary Supplements notes that potassium supplements can cause minor gastrointestinal side effects, so each ingredient can unsettle a stomach on its own. If anything, the fiber is a reason to be more conservative with the potassium.
The directions are one scoop stirred into at least 300 mL of water, at most two scoops a day.
Who should not take supplemental potassium
Healthy kidneys hold blood potassium inside a narrow range and clear whatever is spare. When kidney function is reduced, that clearance slows and potassium that would normally have been excreted stays in the blood. High blood potassium is called hyperkalemia, and at the severe end it disturbs the heart's rhythm.
Several common medicines reduce how much potassium the kidneys excrete, which can push blood potassium up, and some everyday products add more:
- Angiotensin converting enzyme inhibitors, usually shortened to ACE inhibitors. The generic names end in "pril": ramipril, lisinopril, enalapril, perindopril.
- Angiotensin receptor blockers, usually shortened to ARBs. The generic names end in "sartan": losartan, candesartan, irbesartan, valsartan.
- Potassium-sparing diuretics: spironolactone, eplerenone, amiloride, triamterene.
- Low sodium salt substitutes, which are mostly potassium chloride, and any other potassium supplement already in the cupboard. These stack.
The National Institutes of Health Office of Dietary Supplements puts it this way: in people with impaired urinary potassium excretion due to chronic kidney disease or certain medicines, "even dietary potassium intakes below the AI can cause hyperkalemia", AI being the Adequate Intake. Its advice for anyone at risk is to ask a doctor or registered dietitian about potassium intake from all sources.
So if you have reduced kidney function, take any of the medicines above, have been told to limit potassium, or have ever been told your potassium runs high, do not add supplemental potassium without talking to your own doctor first. They can look at your blood tests. We cannot. If you are unsure, a potassium and kidney function blood test is a routine thing to ask for.
For people whose kidneys handle potassium normally, the same fact sheet says high potassium intakes from food pose no health risk, because the kidneys excrete the excess. For people with kidney disease or on these medicines the advice covers total potassium, from food, supplements and salt substitutes together, and a doctor who can see their blood tests is the one to set it.
Where to read the research on potassium and disease risk
This article leaves out the outcome research on potassium. Most of the reason anyone cares about potassium is a large body of population research on disease risk, and we sell a drink containing potassium, which makes us the wrong people to summarize it for you. The trials above are here because they compare one potassium salt with another. For the rest, read the National Institutes of Health fact sheet, or anyone else who is not selling you something.
Sources
- He FJ, Markandu ND, Coltart R, Barron J, MacGregor GA. Effect of short-term supplementation of potassium chloride and potassium citrate on blood pressure in hypertensives. Hypertension. 2005;45(4):571-574. doi:10.1161/01.HYP.0000158264.36590.19. pubmed.ncbi.nlm.nih.gov/15723964
- He FJ, Marciniak M, Carney C, Markandu ND, Anand V, Fraser WD, Dalton RN, Kaski JC, MacGregor GA. Effects of potassium chloride and potassium bicarbonate on endothelial function, cardiovascular risk factors, and bone turnover in mild hypertensives. Hypertension. 2010;55(3):681-688. doi:10.1161/HYPERTENSIONAHA.109.147488. pubmed.ncbi.nlm.nih.gov/20083724
- Braschi A, Naismith DJ. The effect of a dietary supplement of potassium chloride or potassium citrate on blood pressure in predominantly normotensive volunteers. British Journal of Nutrition. 2008;99(6):1284-1292. doi:10.1017/S0007114507864853. pubmed.ncbi.nlm.nih.gov/18053306
- Overlack A, Maus B, Ruppert M, Lennarz M, Kolloch R, Stumpe KO. Potassium citrate versus potassium chloride in essential hypertension: effects on hemodynamic, hormonal and metabolic parameters. In German. Deutsche Medizinische Wochenschrift. 1995;120(18):631-635. doi:10.1055/s-2008-1055388. pubmed.ncbi.nlm.nih.gov/7750429
- Vongpatanasin W, Peri-Okonny P, Velasco A, Arbique D, Wang Z, Ravikumar P, Adams-Huet B, Moe OW, Pak CYC. Effects of potassium magnesium citrate supplementation on 24-hour ambulatory blood pressure and oxidative stress marker in prehypertensive and hypertensive subjects. American Journal of Cardiology. 2016;118(6):849-853. doi:10.1016/j.amjcard.2016.06.041. pubmed.ncbi.nlm.nih.gov/27448942
- Conen K, Scanni R, Gombert MT, Hulter HN, Krapf R. Effects of potassium citrate or potassium chloride in patients with combined glucose intolerance: a placebo-controlled pilot study. Journal of Diabetes and its Complications. 2016;30(6):1158-1161. doi:10.1016/j.jdiacomp.2016.03.017. pubmed.ncbi.nlm.nih.gov/27260862
- Wouda RD, Gritter M, Karsten M, Michels EHA, Nieuweboer TM, Danser AHJ, de Borst MH, Hoorn EJ, Rotmans JI, Vogt L. Kaliuresis and intracellular uptake of potassium with potassium citrate and potassium chloride supplements: a randomized controlled trial. Clinical Journal of the American Society of Nephrology. 2023;18(10):1260-1271. doi:10.2215/CJN.0000000000000228. pubmed.ncbi.nlm.nih.gov/37382933
- Macdonald-Clarke CJ, Martin BR, McCabe LD, McCabe GP, Lachcik PJ, Wastney M, Weaver CM. Bioavailability of potassium from potatoes and potassium gluconate: a randomized dose response trial. American Journal of Clinical Nutrition. 2016;104(2):346-353. doi:10.3945/ajcn.115.127225. pubmed.ncbi.nlm.nih.gov/27413123
- Sinopoli DA, Lawless HT. Taste properties of potassium chloride alone and in mixtures with sodium chloride using a check-all-that-apply method. Journal of Food Science. 2012;77(9):S319-S322. doi:10.1111/j.1750-3841.2012.02862.x. pubmed.ncbi.nlm.nih.gov/22901084
- United States Food and Drug Administration. Potassium salt preparations intended for oral ingestion by man. 21 CFR 201.306. govinfo.gov
- United States Food and Drug Administration. Drug products withdrawn or removed from the market for reasons of safety or effectiveness. 21 CFR 216.24. govinfo.gov
- National Institutes of Health, Office of Dietary Supplements. Potassium: fact sheet for health professionals. Updated 2 June 2022. ods.od.nih.gov
- National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Sodium and Potassium. Washington DC: The National Academies Press, 2019. doi:10.17226/25353. nap.nationalacademies.org
- PubChem, United States National Library of Medicine. Compound records for potassium citrate (CID 2735208), potassium chloride (CID 4873), potassium bicarbonate (CID 516893), potassium gluconate (CID 16760467) and potassium aspartate (CID 71586907). Elemental percentages calculated from the molecular formulas; the potassium chloride solubility figure is from the CRC Handbook of Chemistry and Physics, 95th edition, as cited there; the metabolism of citrate to bicarbonate and the urinary figure are from the potassium citrate record's Pharmacology and Biochemistry section. pubchem.ncbi.nlm.nih.gov
- Joint FAO/WHO Expert Committee on Food Additives. Monograph: potassium hydrogen carbonate. fao.org
- Therapeutic Goods Administration, Australia. Poisons Standard, June 2024 (Standard for the Uniform Scheduling of Medicines and Poisons), Schedule 4 entry for potassium chloride. Federal Register of Legislation F2024L00589. legislation.gov.au
- United States Department of Agriculture, Agricultural Research Service. FoodData Central, SR Legacy. Portion figures calculated from the per 100 gram values. fdc.nal.usda.gov
This article is general information, not medical advice. Potassium Fiber is a drink powder containing 500 mg of potassium as potassium citrate and 8 grams of fiber from acacia gum per serving, on pre-sale and shipping from 1 December 2026.