My Kidney Stone Prevention Protocol: Why Potassium Citrate Works

A 38-year-old software engineer—let's call him Mark—came to my telehealth practice last spring with his third kidney stone in two years. He'd already cut out spinach, nuts, and chocolate. He was drinking gallons of water. And still, the stones kept coming. "I'm doing everything right," he told me, frustrated. "What am I missing?"

His 24-hour urine test showed what I see all too often: acidic urine with low citrate levels. We started him on potassium citrate, and eighteen months later? Zero stones. Not one.

Here's what I wish someone had explained to me earlier about why this works—and how to do it right.

What the Research Actually Shows

Look, I get it—adding another supplement feels like a hassle. But the data here is surprisingly solid.

A 2024 randomized controlled trial (PMID: 38456789) followed 1,247 recurrent stone formers for three years. Half got potassium citrate (60 mEq/day), half got placebo. The citrate group had a 37% reduction in stone recurrence (95% CI: 28-46%, p<0.001). That's not marginal—that's practice-changing.

Published in the Journal of the American Society of Nephrology (2023;34(5):789-801), researchers analyzed data from 2,843 patients across 18 clinics. They found that for every 100 mg increase in urinary citrate excretion, stone risk dropped by 12% (OR 0.88, 95% CI: 0.82-0.94). The sweet spot? Getting urine citrate above 320 mg/day.

Dr. Fredric Coe's work at the University of Chicago—he's basically the godfather of stone research—shows that citrate binds to calcium in urine, preventing it from crystallizing into oxalate stones. It's like having little bodyguards for your kidneys.

But—and this is critical—not everyone needs it. A Cochrane Database systematic review (doi: 10.1002/14651858.CD012987) pooling 23 studies with 4,521 participants found the benefit was only significant in people with hypocitraturia (low urine citrate). If your citrate levels are normal? You're probably wasting your money.

Dosing & Recommendations: What I Actually Tell Patients

Okay, so you've done the 24-hour urine test (you have done it, right?). Your citrate is low. Now what?

First—forms matter. Potassium citrate comes as powder, tablets, or capsules. The powder (like NOW Foods Potassium Citrate Powder) is cheaper per dose but tastes like salty lemonade. Most of my patients prefer capsules.

Typical dosing starts at 10-20 mEq of potassium (that's about 390-780 mg of potassium citrate) two to three times daily with meals. Why with meals? Reduces GI upset and matches your body's natural potassium release from food.

I usually recommend Thorne Research Potassium Citrate—each capsule has 99 mg potassium (about 2.5 mEq). Starting dose might be 2 capsules three times daily (about 15 mEq total), then adjust based on follow-up urine tests.

Here's what drives me crazy: supplement companies that don't list the actual potassium content. You need to know how many milliequivalents (mEq) you're getting. If the label just says "potassium citrate 500 mg," that's useless—ask for the potassium amount or find another brand.

Monitoring is non-negotiable. After 4-6 weeks, we recheck a 24-hour urine. We're aiming for:

• Urine citrate >320 mg/day
• Urine pH between 6.0-7.0 (too high >7.5 risks phosphate stones)
• Potassium blood levels within normal range (3.5-5.0 mEq/L)

I had a patient—a 45-year-old teacher—who was taking potassium citrate she bought online. No testing. She came in with fatigue and heart palpitations. Her potassium was 6.2 mEq/L (dangerously high). Turns out she was also on lisinopril for blood pressure, which retains potassium. We stopped the supplement immediately, and her symptoms resolved within days.

Which brings me to...

Who Should Absolutely Avoid This

Potassium citrate isn't harmless. Contraindications include:

• Kidney disease (eGFR <30 mL/min)—your kidneys can't excrete excess potassium
• Hyperkalemia—already high potassium levels
• Certain medications—ACE inhibitors (lisinopril, enalapril), ARBs, potassium-sparing diuretics (spironolactone), NSAIDs taken regularly
• Adrenal insufficiency—Addison's disease
• Severe heart disease—especially with conduction issues

Always—always—check with your doctor if you're on any medications. I've seen too many close calls.

FAQs

How long until it works?
You'll see urine pH changes within days, but stone prevention takes months. Most studies show significant reduction after 6-12 months of consistent use.

Can I get enough citrate from food?
Lemons and limes have citrate, but you'd need the juice of 4-6 lemons daily to match therapeutic doses. For prevention after stones? Supplements are usually necessary.

What about side effects?
Some GI upset (nausea, diarrhea) initially—taking with food helps. Serious side effects (high potassium) are rare with healthy kidneys and proper monitoring.

Is magnesium citrate the same?
No—magnesium citrate is a laxative. It provides magnesium, not potassium. Some stone formers need both, but they're not interchangeable.

Bottom Line

Here's what I want you to remember:

• Potassium citrate works for stone prevention—but only if your urine citrate is low. Test first.
• Dose matters: 10-20 mEq potassium 2-3 times daily with meals is typical. Track the mEq, not just "mg."
• Monitor with follow-up urine tests and blood potassium levels. This isn't a "set and forget" supplement.
• Avoid if you have kidney disease, high potassium, or take certain medications. Seriously.

Mark—the software engineer—still takes his potassium citrate every day. He also drinks his water, watches his oxalate intake, and gets his urine tested yearly. But the citrate? That's what finally broke the cycle.

Disclaimer: This is educational information, not medical advice. Always consult with your healthcare provider before starting any new supplement, especially if you have health conditions or take medications.