Potassium

Does potassium citrate prevent kidney stones?

Updated 9 Nov 2026

Short answer

In people who already had calcium stones, yes. In a 2015 Cochrane review of 7 trials with 477 people, citrate salts cut the risk of new stones to about a quarter (risk ratio 0.26).[1] The citrate, not the potassium, is thought to prevent the stones.[2]

What the trials found

  • 2015 Cochrane review. 7 trials with 477 adults, most with calcium oxalate stones. Three trials tested potassium citrate, three potassium-sodium citrate and one potassium-magnesium citrate, for at least 6 months.[1] New stones formed less often with citrate (risk ratio 0.26), stones shrank more often (risk ratio 2.35), and fewer people needed treatment again (risk ratio 0.22). The authors rated the quality of the trials as moderate to poor.[1]
  • A 3-year placebo trial. 57 people had 2 or more stones in the previous 2 years and low citrate in urine. They took 30 to 60 mEq of potassium citrate a day in wax-matrix tablets, or a placebo.[3] With potassium citrate, new stones fell from 1.2 to 0.1 per person a year, and 72% were in remission. With placebo, the rate stayed at 1.1, and 20% were in remission.[3]
  • After shock wave treatment. A 2017 review of 4 trials with 374 people found fewer new stones over 12 months with about 55 mEq of potassium citrate a day (risk ratio 0.21). The quality of the trials was low.[4]
  • 2025 umbrella review. A review of reviews found that potassium citrate lowered the risk of new stones by 79%, with high certainty of evidence.[5]

Cohort studies point the same way for potassium from food. Men who ate 4,042 mg a day or more had a 51% lower risk of stones over 4 years than men who ate 2,895 mg or less. Women who ate more than 4,099 mg a day had a 35% lower risk over 12 years.[2] A US government review (AHRQ) found only one supplement trial that met its rules, and called the evidence for supplements insufficient.[2]

Why it may work

  1. Potassium citrate raises the amount of citrate in urine.[3]
  2. Citrate binds calcium in urine and makes urine less acidic (higher pH).[2]
  3. With less free calcium and a higher pH, calcium oxalate crystals form less easily.[2]

A low potassium intake also makes the kidneys keep less calcium, so more calcium goes into urine.[2]

Side effects

In the Cochrane review, the main side effect was stomach upset. More people stopped citrate than control treatment because of side effects (risk ratio 4.45).[1] In the 3-year trial, 2 people on potassium citrate and 1 on placebo stopped because of side effects, which were mild.[3]

Who should be careful

The trial doses, 30 to 60 mEq a day (1,173 to 2,346 mg of potassium), are far above the 99 mg in most supplements.[2] People with kidney disease, or who take ACE inhibitors, angiotensin receptor blockers (ARBs) or potassium-sparing diuretics, can develop high blood potassium.[2] They should ask a doctor before they take potassium citrate.[2]

What is still unknown

The Cochrane authors ask for a large, well-designed trial in several centres to answer the open questions.[1]

Sources (5)

  1. Citrate salts for preventing and treating calcium containing kidney stones in adults. Phillips R, Hanchanale VS, Myatt A, Somani B, Nabi G, Biyani CS Cochrane Database Syst Rev, 2015. PMID 26439475
  2. Potassium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  3. Randomized double-blind study of potassium citrate in idiopathic hypocitraturic calcium nephrolithiasis. Barcelo P, Wuhl O, Servitge E, Rousaud A, Pak CY J Urol, 1993. PMID 8230497
  4. Effect of potassium citrate supplement on stone recurrence before or after lithotripsy: systematic review and meta-analysis. Carvalho M, Erbano BO, Kuwaki EY, Pontes HP, Liu JWTW, Boros LH, et al. Urolithiasis, 2017. PMID 27915395
  5. Preventing and treating kidney stones: an umbrella review of meta-analyses of non-surgical randomized controlled trials. Veronese N, Ciriminna S, Errera CM, Garlisi MC, Tulone O, Sapienza V, et al. Minerva Urol Nephrol, 2025. PMID 40891477

More about potassium

What is potassium?Which foods contain potassium?What is potassium used for?What happens if you do not get enough potassium?Is potassium safe?Why do potassium supplements contain only 99 mg?

For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.