What does the research show about potassium?

Potassium

Higher potassium intake lowered systolic pressure 3.5 mm Hg, mainly with hypertension. Supplements lowered clinic pressure 5.3 mm Hg in untreated hypertension, and salt substitutes about 4.6 to 4.8 mm Hg. In a trial of 20,995 people, stroke, heart events and death fell. Trials excluding people at risk found no rise in hyperkalemia. Case reports link it to kidney disease.

Add to Bio HackChecked 2026-11-09

Status: Dietary supplement in the US. Salt substitutes are sold as food. Higher-dose potassium chloride and potassium citrate tablets are prescription drugs.
Also called: potassium chloride, KCl, potassium citrate, potassium bicarbonate, potassium gluconate, salt substitute, low-sodium salt, potassium-enriched salt, lite salt, NoSalt, Nu-Salt
Taken for: blood pressure, stroke prevention, heart health, replacing salt, bone health, muscle cramps, electrolytes

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help3

StrongShown to lower blood pressure about 3.5 mmHg systolic and 2 mmHg diastolic in people with hypertension, with little effect in people without it.
ModerateShown to lower stroke about 14% and death about 12% with a potassium salt substitute, mostly from one trial in older rural Chinese adults at high stroke risk.
LimitedOne open-label trial found fewer arrhythmia events, hospitalizations and deaths when potassium was raised with supplements or a drug in adults with a defibrillator.

Reported risks3

ModerateShown to raise adverse events in people with untreated hypertension, 12.8% against 3.2% on control, with few withdrawals.Very common
ModerateSalt substitutes raised blood potassium slightly, and hyperkalemia was about as common as on regular salt. Trials excluded people at known risk.Common
LimitedCase reports: life-threatening high potassium occurred with kidney disease or potassium-sparing drugs. A small trial found larger potassium rises in chronic kidney disease.How often is not known

What people take it for, and what was found

Shown to help3

Strong

Blood pressure

Shown to lower blood pressure about 3.5 mmHg systolic and 2 mmHg diastolic in people with hypertension, with little effect in people without it.

The numbers and sources

Effect: Increased potassium intake lowered systolic pressure 3.49 mm Hg (95% CI 1.82 to 5.15) and diastolic 1.96 mm Hg (95% CI 0.86 to 3.06), an effect seen in people with hypertension and not in those without it [1]. Salt substitutes lowered systolic pressure 4.61 mm Hg (95% CI 3.14 to 6.07) and diastolic 1.61 mm Hg in one meta-analysis [2], and 4.76 mm Hg systolic and 2.43 mm Hg diastolic in a Cochrane review [3]. In untreated primary hypertension, oral potassium supplements lowered clinic systolic pressure 5.3 mm Hg (95% CI 4.4 to 6.3) and diastolic 4.5 mm Hg (95% CI 3.9 to 5.1). The drop in 24-hour ambulatory pressure was smaller, 2.8 mm Hg systolic and 3.2 mm Hg diastolic [4]. In a dose-response analysis of 10 RCTs, each 50 mmol a day rise in urinary potassium went with 5.3 mm Hg lower systolic pressure in people with hypertension and 0.5 mm Hg lower in people without it [5].
Population: 22 RCTs with 1,606 adults [1]; 19 trials reporting blood pressure [2]; 20 RCTs with 21,414 adults [3]; 19 trials with 803 adults, median 4 weeks [4]; 10 RCTs from 2000 to 2024 [5].
Sources: [1], [2], [3], [4], [5]
Caveats: Each 10% lower share of sodium chloride in a salt substitute was linked to a further 1.53 mm Hg drop in systolic pressure [2]. In children, the change was 0.28 mm Hg and not significant [1]. Heterogeneity was substantial and follow-up short in [4]. The dose-response review rested on few trials [5].

Moderate

Stroke, heart events and death

Shown to lower stroke about 14% and death about 12% with a potassium salt substitute, mostly from one trial in older rural Chinese adults at high stroke risk.

The numbers and sources

Effect: Stroke was lower on a salt substitute of 75% sodium chloride and 25% potassium chloride than on regular salt (29.14 against 33.65 per 1,000 person-years, rate ratio 0.86, 95% CI 0.77 to 0.96). Major cardiovascular events (rate ratio 0.87) and death (rate ratio 0.88, 95% CI 0.82 to 0.95) were also lower [6]. Pooled trials found lower total mortality (RR 0.89, 95% CI 0.85 to 0.94) and cardiovascular events (RR 0.89) [2]. In cohort studies, higher potassium intake went with a 24% lower stroke risk (RR 0.76, 95% CI 0.66 to 0.89) [1]. In a post hoc analysis of the same trial, total cancer did not differ (RR 0.94, 95% CI 0.81 to 1.08), and stomach cancer showed a non-significant trend lower (RR 0.77, 95% CI 0.54 to 1.08) [7].
Population: 20,995 people in 600 rural Chinese villages with prior stroke, or aged 60 or older with high blood pressure, mean follow-up 4.74 years [6][7]; 5 trials reporting clinical outcomes [2]; 11 cohorts with 127,038 people [1].
Sources: [1], [2], [6], [7]
Caveats: One trial carries most of the clinical events, and it enrolled people at high stroke risk. Cochrane rated the effects as slight and the certainty moderate [3]. The trial was funded by Australia's National Health and Medical Research Council [6].

Limited

Heart rhythm in people with a defibrillator

One open-label trial found fewer arrhythmia events, hospitalizations and deaths when potassium was raised with supplements or a drug in adults with a defibrillator.

The numbers and sources

Effect: In 1,200 adults with an implantable defibrillator and plasma potassium of 4.3 mmol/L or lower, a strategy of raising potassium to 4.5 to 5.0 mmol/L with potassium supplements, a mineralocorticoid receptor antagonist or both lowered the composite of sustained ventricular tachycardia or appropriate shocks, unplanned hospitalization for arrhythmia or heart failure, and death: 22.7% against 29.2% on standard care (HR 0.76, 95% CI 0.61 to 0.95) over a median 39.6 months [8]. Atrial fibrillation events were 8.0% against 12.2% (subdistribution HR 0.65, 95% CI 0.45 to 0.93) [9]. Among those on potassium supplements alone, 21% reached the primary endpoint, against 29% of controls [10].
Population: 1,200 adults with cardiac disease and a defibrillator in Denmark, POTCAST trial [8][9][10].
Sources: [8], [9], [10]
Caveats: One open-label trial in a high-risk group. The strategy combined supplements and a prescription drug, so the effect of potassium supplements alone was not randomized [10]. Funded by the Independent Research Fund Denmark and others [8].
Why limited: This rests on one trial, of 1,200 people. Strength counts independent studies that agree, so one trial is limited at any size.

Mixed results1

Limited

Bone

Limited evidence: alkaline potassium salts lowered a bone breakdown marker, with bone density unchanged in a review and up 1.7% in one trial. No fracture data.

The numbers and sources

Effect: Sources disagree. A meta-analysis of 14 studies found potassium bicarbonate and citrate lowered urinary calcium and the bone breakdown marker NTX, with no effect on bone density [11]. In one 2-year trial, 60 mEq of potassium citrate a day raised lumbar spine density 1.7% over placebo (95% CI 1.0 to 2.3) [12]. In 5 RCTs of postmenopausal women, potassium citrate lowered urinary NTX at 1 month (MD -4.05 nmol BCE/mmol creatinine, 95% CI -8.05 to -0.05). CTX, P1NP, urinary calcium and parathyroid hormone did not differ from placebo [13].
Population: 14 studies of alkaline potassium salts [11]; 201 healthy adults over 65 without osteoporosis, all given calcium and vitamin D [12]; 401 postmenopausal women [13].
Sources: [11], [12], [13]
Caveats: No fracture outcomes. Potassium chloride, the form in salt substitutes, lowered urinary calcium less than the alkaline salts [11].

Not shown to help1

Limited

Muscle cramps

Limited evidence: no trial of potassium for cramps was located, and cohort studies found athletes who cramped had higher, not lower, blood potassium after races.

Compared with athletes who did not cramp [18][19]

The numbers and sources

Effect: A 2026 meta-analysis of 9 longitudinal studies (11,274 participants) found higher post-race serum potassium in people with exercise-associated cramps (moderate evidence). Apart from a history of cramps, no hydration, electrolyte or other factor was consistently linked to cramping [18]. An earlier review found that support for the electrolyte depletion explanation of exercise cramps came mainly from anecdotes, case series totaling 18 cases and one case-control study of 10, while four prospective cohort studies did not support it [19].
Population: 11,274 participants in 9 longitudinal studies of athletes [18]. Studies of exercise-associated cramps [19].
Sources: [18], [19]
Caveats: Observational studies of blood levels, not trials of taking potassium. The authors of [18] rated most findings as limited or very limited evidence. Cramps in other settings, such as at night or during dialysis, were not covered.

Doses studied

In the blood pressure meta-analysis, systolic pressure fell 7.16 mm Hg (95% CI 1.91 to 12.41) when the higher intake was 90 to 120 mmol a day, without a dose response [1]. The stroke trial used a substitute of 75% sodium chloride and 25% potassium chloride by mass [6]. Salt substitutes in trials replaced about 3% to 77% of sodium chloride [3]. The bone trial used 60 mEq of potassium citrate a day [12]. EFSA found no adequate data to derive a tolerable upper intake level for potassium [14].

Risks

Reported risks2

ModerateVery common

Side effects of potassium supplements

Shown to raise adverse events in people with untreated hypertension, 12.8% against 3.2% on control, with few withdrawals.

The numbers and sources

How common: Very common: more than 1 in 10 people.
Effect: In trials of untreated primary hypertension, adverse events were more frequent on potassium than control (12.8% against 3.2%). Withdrawals, including withdrawals for adverse events, were uncommon [4].
Population: 19 trials with 803 adults [4].
Sources: [4]
Caveats: The review describes safety data as limited [4]. The abstract does not name the adverse events.

LimitedHow often is not known

Hyperkalemia with kidney disease and potassium-sparing drugs

Case reports: life-threatening high potassium occurred with kidney disease or potassium-sparing drugs. A small trial found larger potassium rises in chronic kidney disease.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: In a crossover trial, a single 40 mmol oral dose of potassium chloride or potassium citrate raised plasma potassium more in 9 patients with stage 3b to 4 chronic kidney disease than in 18 healthy adults, and did not raise sodium excretion in the patients [15]. An 88-year-old man with chronic kidney disease reached a potassium of 7.5 mEq/L after eating a potassium-enriched salt substitute his family brought to the hospital [16]. Two patients after cardiac surgery with normal kidney function developed life-threatening hyperkalemia while taking an ACE inhibitor, a potassium-sparing diuretic and a high-potassium diet [17].
Population: 27 adults in a placebo-controlled crossover trial [15]. Case reports, 3 patients [16][17].
Sources: [15], [16], [17]
Caveats: The trial measured 4 hours after one dose [15]. Case reports show that the event can happen, not how often.

Mixed results1

ModerateCommon

Raised blood potassium and hyperkalemia

Salt substitutes raised blood potassium slightly, and hyperkalemia was about as common as on regular salt. Trials excluded people at known risk.

The numbers and sources

How common: Common: between 1 in 100 and 1 in 10 people.
Effect: Salt substitutes raised blood potassium by 0.12 mmol/L (95% CI 0.07 to 0.18) and made little to no difference in hyperkalemia (4 more per 100,000, 95% CI 47 fewer to 121 more) [3]. In the stroke trial, serious adverse events attributed to hyperkalemia were 3.35 against 3.30 per 1,000 person-years (rate ratio 1.04, 95% CI 0.80 to 1.37) [6]. Increased potassium intake had no adverse effect on kidney function in adults [1]. In POTCAST, hospitalization for high or low potassium was similar between groups [8]. Hyperkalemia occurred in 3% of those on potassium supplements alone and 0.2% of controls [10].
Population: 784 adults in 6 RCTs for blood potassium, 22,849 in 5 RCTs for hyperkalemia [3]; 20,995 people [6]; 1,200 adults with a defibrillator [8][10].
Sources: [1], [3], [6], [8], [10]
Caveats: All 26 trials in the Cochrane review excluded people in whom extra potassium is known to be harmful. The reviewers found no evidence in those people, or in pregnant women [3].

Claims tested and not found

That potassium lowers blood pressure in people without hypertension. The pooled effect was seen in people with hypertension and not in those without it [1]. A dose-response analysis found 0.5 mm Hg lower systolic pressure per 50 mmol a day in people without hypertension [5].
That alkaline potassium salts raise bone density. Pooled studies found no effect on bone density [11].

Sources

Aburto NJ, Hanson S, Gutierrez H, et al. Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ. 2013. https://doi.org/10.1136/bmj.f1378
Yin X, Rodgers A, Perkovic A, et al. Effects of salt substitutes on clinical outcomes: a systematic review and meta-analysis. Heart. 2022. https://doi.org/10.1136/heartjnl-2022-321332
Brand A, Visser ME, Schoonees A, et al. Replacing salt with low-sodium salt substitutes (LSSS) for cardiovascular health in adults, children and pregnant women. Cochrane Database of Systematic Reviews. 2022. https://doi.org/10.1002/14651858.CD015207
Ravichagua Ashiyama J, Medina FA, Loza C, et al. Oral Potassium Supplementation Lowers Clinic Blood Pressure in Untreated Primary Hypertension: Systematic Review and Meta-Analysis of Randomized Trials. Journal of the American Heart Association. 2026. https://doi.org/10.1161/jaha.125.048590
Granal M, Sourd V, Burnier M, et al. Effect of changes in potassium intake on blood pressure: a dose-response meta-analysis of randomized clinical trials (2000 to 2024). Clinical Kidney Journal. 2025. https://doi.org/10.1093/ckj/sfaf173
Neal B, Wu Y, Feng X, et al. Effect of Salt Substitution on Cardiovascular Events and Death. New England Journal of Medicine. 2021. https://doi.org/10.1056/NEJMoa2105675
Zhang X, Yin X, Yap ML, et al. Effect of sodium-reduced potassium-enriched salt substitutes on stomach cancer: the Salt Substitute and Stroke Study (SSaSS). BMC Medicine. 2025. https://doi.org/10.1186/s12916-025-04068-0
Jøns C, Zheng C, Winsløw UCG, et al. Increasing the Potassium Level in Patients at High Risk for Ventricular Arrhythmias. New England Journal of Medicine. 2025. https://doi.org/10.1056/nejmoa2509542
Zheng C, Winsløw UCG, Danielsen EM, et al. Increasing plasma potassium and risk of atrial fibrillation: the POTCAST trial. European Heart Journal. 2026. https://doi.org/10.1093/eurheartj/ehag436
Danielsen EM, Frandsen EA, Winsløw UCG, et al. Potassium-increasing regimens in patients at high risk of ventricular arrhythmias: a prespecified observational analysis of the randomized POTCAST trial. Europace. 2026. https://doi.org/10.1093/europace/euag272
Lambert H, Frassetto L, Moore JB, et al. The effect of supplementation with alkaline potassium salts on bone metabolism: a meta-analysis. Osteoporosis International. 2015. https://doi.org/10.1007/s00198-014-3006-9
Jehle S, Hulter HN, Krapf R. Effect of Potassium Citrate on Bone Density, Microarchitecture, and Fracture Risk in Healthy Older Adults without Osteoporosis: A Randomized Controlled Trial. Journal of Clinical Endocrinology & Metabolism. 2013. https://doi.org/10.1210/jc.2012-3099
AlSejari N, Alkhulaifi NS, Alenezi RS, et al. Effects of Potassium Citrate Supplementation on Bone Turnover Markers in Postmenopausal Women: A GRADE-Assessed Systematic Review, Meta-analysis and Trial Sequential Analysis. Calcified Tissue International. 2026. https://doi.org/10.1007/s00223-026-01569-9
European Food Safety Authority. Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF) and the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Version 11. 2025. https://www.efsa.europa.eu/sites/default/files/assets/UL_Summary_tables.pdf
Wouda RD, Karsten M, Michels EHA, et al. Natriuretic response to an acute oral potassium load in healthy individuals and patients with chronic kidney disease: a randomized controlled trial. Nephrology Dialysis Transplantation. 2025. https://doi.org/10.1093/ndt/gfaf238
Kusunoki M, Fujihara T, Ishida R, et al. Hyperkalemia Caused by Potassium-Enriched Salt in a Hospitalized Patient. Cureus. 2025. https://doi.org/10.7759/cureus.86704
Dixit A, Majumdar G, Tewari P. Hyperkalemia in ambulant postcardiac surgery patients during combined therapy with angiotensin-converting enzyme inhibitor, spironolactone, and diet rich in potassium: A report of two cases and review of literature. Annals of Cardiac Anaesthesia. 2019. https://doi.org/10.4103/aca.aca_65_18
Costa LDS, Correa VAF, de Oliveira VF, et al. Risk Factors for Exercise-Associated Muscle Cramps: A Systematic Review With Meta-Analysis. Muscle & Nerve. 2026. https://doi.org/10.1002/mus.70389
Schwellnus MP. Cause of exercise associated muscle cramps (EAMC): altered neuromuscular control, dehydration or electrolyte depletion? British Journal of Sports Medicine. 2009. https://doi.org/10.1136/bjsm.2008.050401

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