Potassium (chloride vs citrate vs gluconate)
Summary
Most potassium supplements contain 99 mg or less, far below the adult AI of 2,600-3,400 mg. Gluconate was about 94% absorbed, like potassium from potatoes. Trials of larger prescribed amounts lowered blood pressure, mostly in people with high readings, and a potassium-enriched salt substitute cut heart events. Bone results with potassium citrate are mixed.
Key facts
- Potassium chloride (most common), citrate, gluconate, bicarbonate, phosphate, aspartate; potassium-enriched salt substitutes[1]
- Gluconate is absorbed >94%, as well as potassium from potatoes. Citrate and bicarbonate are alkaline salts studied for bone and urinary stones; chloride is used in blood-pressure trials and salt substitutes[8][1]
- Blood pressure ↓ in people not on medication (A); a Cochrane review of 6 small trials was not significant (C); heart events ↓ with a salt substitute (B); new calcium stones ↓ with citrate salts (C); bone density mixed (C)[2][3][4][7][5][6]
- Most supplements contain ≤99 mg because FDA linked some potassium chloride drug products above 99 mg to small-bowel lesions[1]
- 3,400 mg (men), 2,600 mg (women); 2,900 mg in pregnancy and 2,800 mg while breastfeeding (19+). No UL has been set[1]
- ACE inhibitors, ARBs and potassium-sparing diuretics (high potassium); loop and thiazide diuretics (low potassium)[1]
- 6 graded human outcomes on this page
- October 8, 2026
How it works
EstablishedPotassium is the main positively charged ion inside cells. The gradient between high intracellular and low extracellular potassium, maintained by the sodium-potassium pump, sets cell membrane potential for nerve transmission, muscle contraction and kidney function (established). Higher intakes may lower blood pressure partly by increasing blood-vessel dilation and urinary sodium excretion (proposed).[1]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Heart | Grade A | Worsened | Meta-analysis · n = 917 · 2015 | 3 rows |
| Bones & joints | Grade C | Worsened | Systematic review · n = 477 · 2015 | 3 rows |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Blood pressure in adults not on blood-pressure medicines | Worsened | Grade A | Meta-analysis · n = 917 · 2015 Patients without antihypertensive medication in 15 randomized trials; normal or high blood pressure Form: potassium supplements (mostly potassium chloride, per ODS) · Dose: Varied; the effect tracked a rise in urinary potassium from 60 to 100 mmol/day · Duration: Varied across trials Systolic blood pressure fell by 4.7 mmHg and diastolic by 3.5 mmHg overall; in hypertensive patients by 6.8 and 4.6 mmHg. | 26039623 (opens PubMed)Source [2] |
| Major heart and blood-vessel events with a potassium-enriched salt substitute | Worsened | Grade B | RCT · n = 20,995 · 2021 Adults in 600 rural Chinese villages with a history of stroke, or aged 60+ with high blood pressure Form: salt substitute (75% sodium chloride, 25% potassium chloride) · Dose: Used in place of regular salt · Duration: Mean follow-up 4.74 years Stroke (rate ratio 0.86; 95% CI 0.77 to 0.96), major cardiovascular events (0.87) and death (0.88) were lower than with regular salt. Serious adverse events from high potassium were not significantly increased. | 34459569 (opens PubMed)Source [4] |
| Blood pressure in a review of 6 small trials | Mixed | Grade C | Systematic review · n = 483 · 2006 Adults with primary hypertension in 6 randomized trials Form: potassium supplements · Dose: Varied across trials · Duration: 8 to 16 weeks Reductions in systolic (-11.2 mmHg) and diastolic (-5.0 mmHg) blood pressure were large but not statistically significant, with substantial unexplained heterogeneity. | 16856053 (opens PubMed)Source [3] |
| New calcium-containing urinary stones with citrate salts | Worsened | Grade C | Systematic review · n = 477 · 2015 Adults with calcium-containing (mostly oxalate) stones in 7 studies Form: potassium citrate, potassium-sodium citrate or potassium-magnesium citrate · Dose: Varied across trials · Duration: Varied across trials New stone formation was lower with citrate therapy (RR 0.26; 95% CI 0.10 to 0.68; 7 studies, 324 participants) and stone size was more often reduced. GI side effects were more common but not significantly. | 26439475 (opens PubMed)Source [7] |
| Bone turnover and density in postmenopausal women | No effect | Grade C | RCT · n = 276 · 2008 Healthy postmenopausal women aged 55-65 Form: potassium citrate (two strengths) vs extra fruit and vegetables vs placebo · Dose: 18.5 or 55.5 mEq/d potassium citrate · Duration: 2 years No reduction in bone turnover markers and no difference in spine or hip bone loss vs placebo. | 18689384 (opens PubMed)Source [6] |
| Bone density in healthy adults over 65 | Improved | Grade C | RCT · n = 201 · 2013 Healthy men and women older than 65 without osteoporosis Form: potassium citrate (with calcium and vitamin D in both groups) · Dose: 60 mEq potassium citrate daily · Duration: 24 months Lumbar spine bone density rose 1.7% net of placebo, with gains in trabecular density and microarchitecture at the tibia and radius. | 23162100 (opens PubMed)Source [5] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Potassium chloride | Varies[1] | No head-to-head human data vs other salts in our sources; ODS reports liquid forms are absorbed within a few hours.[1] | Some potassium chloride drug products above 99 mg were linked to small-bowel lesions (FDA).[1] | Most blood-pressure trials (per ODS); salt substitutes |
| Potassium citrate | Varies[1] | No head-to-head human data in our sources.[1] | Upper GI upset was the main side effect in citrate stone trials.[7] | Bone and urinary-stone trials |
| Potassium gluconate | Varies[1] | Absorption efficiency >94%, the same as potassium from potatoes, in a crossover trial of 35 adults.[8] | No form-specific tolerance data in our sources.[1] | Bioavailability |
| Potassium bicarbonate | Varies[1] | No head-to-head human data in our sources.[1] | No form-specific tolerance data in our sources.[1] | Bone-turnover markers in older adults (per ODS) |
Studied doses
Doses studied in human trials ranged from about 723 to 2,346 mg/day of potassium as potassium citrate, for 8 weeks to 2 years; blood-pressure trials used up to about 4,700 mg/day, usually as potassium chloride. These are prescribed amounts, far above the 99 mg typical of supplements.[5][6][3][1]
Intake reference: Adult AI: 3,400 mg/day for men and 2,600 mg/day for women; 2,900 mg in pregnancy and 2,800 mg while breastfeeding (ages 19+). No UL has been established.[1] No UL is set for potassium from food. The AIs do not apply to people whose kidneys or medicines impair potassium excretion; very high supplement or salt-substitute intakes can exceed the kidneys' capacity even in healthy people. NIH ODS fact sheet (updated June 2, 2022).
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Medicines
- ACE inhibitors and angiotensin receptor blockersNIH fact sheetReduce urinary potassium excretion and can lead to high blood potassium; experts advise monitoring, especially with impaired kidney function.[1]
- Potassium-sparing diureticsNIH fact sheetReduce potassium excretion and can cause high blood potassium.[1]
Medicines that can lower levels
- Loop and thiazide diureticsNIH fact sheetIncrease urinary potassium loss and can cause low blood potassium; experts advise monitoring and supplementing if warranted.[1]
Who should be careful
- Kidney problems and certain medicines
- People with impaired kidney function, or taking ACE inhibitors, ARBs or potassium-sparing diuretics, can develop dangerously high blood potassium from supplements or potassium salt substitutes and should use them only with medical advice.[1]
- Gut effects
- Potassium supplements can cause minor GI side effects; some potassium chloride drug products were associated with small-bowel lesions, obstruction and bleeding.[1]
- Salt substitutes
- Salt substitutes contain about 440 to 2,800 mg potassium per teaspoon; ODS advises people with kidney disease or on certain medicines to check with a clinician first.[1]
- Before you start
- Talk to your pharmacist or clinician before adding this supplement, especially if you take prescription medicines, are pregnant or breastfeeding, or have a chronic health condition.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Articles about Potassium (chloride vs citrate vs gluconate)
Plain-English answers to common questions, built on the evidence above.
Frequently asked questions
Why do potassium supplements only have 99 mg?
FDA ruled that some potassium chloride drug products above 99 mg were unsafe because of small-bowel lesions, and requires a warning on some potassium salts above 99 mg. Many supplement makers cap products at 99 mg, about 2% of the Daily Value, although FDA has not ruled on supplements specifically.[1]
Which form of potassium is absorbed most?
Few studies compare forms. Potassium gluconate was absorbed at >94%, as well as potassium from potatoes. Citrate and bicarbonate are alkaline salts studied for bone and urinary-stone outcomes; chloride is used in most blood-pressure trials.[8][1]
Does potassium lower blood pressure?
In most trials, yes: a meta-analysis of 15 trials found reductions of 4.7/3.5 mmHg overall and 6.8/4.6 mmHg in people with high blood pressure not on medication. A 2006 Cochrane review of six small, short trials found no statistically significant effect.[2][9][3]
Are potassium salt substitutes safe?
In a trial of 20,995 older adults in rural China, a salt substitute with 25% potassium chloride lowered stroke, heart events and death without a significant rise in serious high-potassium events. People with kidney disease or on potassium-raising medicines should check with a clinician first.[4][1]
How much potassium do adults need?
The AI is 3,400 mg/day for men and 2,600 mg/day for women, mostly from foods such as fruits, vegetables, dairy and legumes. No UL is set.[1]
Sources
- [1]Potassium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2022. fact-sheet
- [2]Daily potassium intake and sodium-to-potassium ratio in the reduction of blood pressure: a meta-analysis of randomized controlled trials.. J Hypertens, 2015. meta-analysis
- [3]Potassium supplementation for the management of primary hypertension in adults.. Cochrane Database Syst Rev, 2006. systematic-review
- [4]Effect of Salt Substitution on Cardiovascular Events and Death.. N Engl J Med, 2021. RCT
- [5]Effect of potassium citrate on bone density, microarchitecture, and fracture risk in healthy older adults without osteoporosis: a randomized controlled trial.. J Clin Endocrinol Metab, 2013. RCT
- [6]Effect of potassium citrate supplementation or increased fruit and vegetable intake on bone metabolism in healthy postmenopausal women: a randomized controlled trial.. Am J Clin Nutr, 2008. RCT
- [7]Citrate salts for preventing and treating calcium containing kidney stones in adults.. Cochrane Database Syst Rev, 2015. systematic-review
- [8]Bioavailability of potassium from potatoes and potassium gluconate: a randomized dose response trial.. Am J Clin Nutr, 2016. crossover-RCT
- [9]The effect of potassium supplementation on blood pressure in hypertensive subjects: A systematic review and meta-analysis.. Int J Cardiol, 2017. meta-analysis
What changed
- First draft. Every evidence-row PMID checked with NCBI E-utilities (esummary + efetch abstract) and re-read in an independent adversarial pass.