What Supplement Is Good For Preventing Kidney Stones? An Evidence-Based Guide

October 25, 2025 •

5 min read

According to the National Kidney Foundation, producing at least 2 to 2.5 liters of urine daily can reduce kidney stone risk by 50%. Beyond essential hydration, many people wonder what supplement is good for preventing kidney stones to proactively support their renal health.

Quick Summary

Several supplements, including potassium citrate and magnesium citrate, have shown efficacy in preventing certain types of kidney stones by altering urine composition. Probiotics and fish oil also offer potential benefits for specific stone types, though consultation with a doctor is crucial before starting any new regimen.

Key Points

Potassium Citrate: This is a powerful, doctor-prescribed supplement that increases urinary citrate and pH, effectively preventing calcium, uric acid, and cystine stones.
Magnesium Citrate: By binding to oxalate in the intestines and urine, magnesium citrate can help prevent calcium oxalate kidney stones, especially for those with low magnesium levels.
Vitamin B6: As a cofactor in oxalate metabolism, sufficient intake of Vitamin B6 (pyridoxine) can help reduce the body's endogenous production of oxalate.
Probiotics: Some beneficial gut bacteria, particularly Oxalobacter formigenes, may degrade oxalate in the gut, thereby reducing its absorption and urinary excretion.
Avoid High-Dose Vitamin C: High doses of supplemental Vitamin C can be converted to oxalate in the body, increasing the risk of stone formation.
Dietary Calcium is Key: Do not restrict calcium from food, as it binds to oxalate in the gut and prevents its absorption. Low dietary calcium can increase stone risk.
Lifestyle is Foundational: Supplements are secondary to a preventative strategy centered on high fluid intake, a low-sodium diet, and moderate animal protein consumption.

Understanding Kidney Stone Formation

Kidney stones, or nephrolithiasis, are hard, crystalline deposits that form inside the kidneys and can cause severe pain. They occur when there is an imbalance in urine composition, leading to the supersaturation of certain minerals and salts that can crystallize over time. The most common types are calcium oxalate and calcium phosphate stones, but uric acid stones and less common types like cystine stones also exist.

Prevention strategies primarily focus on diluting the urine and modifying its chemical properties to inhibit crystal formation. While diet and hydration are the foundation, certain supplements can play a targeted role in managing specific risk factors, such as low urinary citrate (hypocitraturia) or high urinary oxalate (hyperoxaluria).

Key Supplements for Kidney Stone Prevention

Potassium Citrate

Potassium citrate is often prescribed by doctors for patients with a history of recurrent calcium stones, particularly those with low urinary citrate levels.

How it works: Citrate is a potent natural inhibitor of calcium stone formation. When taken as a supplement, potassium citrate increases urinary citrate and pH, which serves two main functions: it binds to urinary calcium, preventing it from binding with oxalate or phosphate, and it directly inhibits the growth of calcium oxalate crystals.
Benefits: Clinically proven to reduce the risk of calcium stone recurrence. It also effectively alkalinizes the urine, which is crucial for preventing uric acid stones that form in an acidic environment.
Administration: Typically available as an extended-release tablet and taken with meals.

Magnesium Citrate

Magnesium is a mineral that many individuals do not consume in sufficient quantities. Magnesium citrate is a well-regarded form for kidney stone prevention, especially for calcium oxalate stones.

How it works: Magnesium can help prevent calcium oxalate stones by several mechanisms. It binds to oxalate in the intestines, which reduces its absorption and subsequent excretion in the urine. It also competes with calcium to bind with oxalate in the urine, forming more soluble magnesium oxalate complexes.
Benefits: Corrects low magnesium levels often observed in stone formers and may inhibit calcium oxalate crystallization.
Administration: It is recommended to take magnesium with meals to maximize its effect on binding intestinal oxalate.

Vitamin B6 (Pyridoxine)

Vitamin B6 plays a critical role in oxalate metabolism, and supplementation has been studied for its potential to reduce urinary oxalate levels.

How it works: Vitamin B6 is a cofactor for enzymes involved in the metabolic pathway that prevents the body from producing excess oxalate. A deficiency can lead to increased endogenous oxalate production.
Benefits: Studies have shown an inverse relationship between vitamin B6 intake and the risk of stone formation, especially in women.
Administration: Dosage recommendations vary, with some studies showing benefits at 50 mg/day, but amounts should be discussed with a doctor, especially for higher doses.

Probiotics

Emerging research suggests a link between gut microbiota and kidney stone risk. Certain probiotics may offer a non-pharmacological approach to reducing oxalate absorption.

How it works: Certain bacteria, such as Oxalobacter formigenes and some Lactobacillus and Bifidobacterium species, have the ability to degrade oxalate in the gut. By breaking down oxalate in the intestine, these probiotics can reduce the amount of oxalate absorbed into the bloodstream and subsequently excreted by the kidneys.
Benefits: May help lower urinary oxalate levels, particularly in individuals with hyperoxaluria.
Evidence: While early evidence is promising, larger human trials are still needed to confirm efficacy.

Fish Oil (Omega-3 Fatty Acids)

Some studies suggest a role for fish oil in kidney stone prevention, although the evidence is less conclusive than for citrates.

How it works: Fish oil, rich in eicosapentaenoic acid (EPA), may influence urinary chemistry. Research has shown that supplementation can lead to decreased urinary calcium and oxalate concentrations while increasing urinary citrate. This is thought to be mediated by the inhibition of certain prostaglandins that can promote hypercalciuria.
Benefits: Potential to positively modulate multiple urinary risk factors for stone formation.

Caution with Other Supplements

It is critical to be cautious with certain supplements that can worsen kidney stone risk. High doses of Vitamin C (ascorbic acid) can be metabolized into oxalate, increasing urinary oxalate excretion and the risk of calcium oxalate stones. Similarly, while adequate calcium intake from food is protective, excessive calcium supplementation may increase stone risk, especially when taken without food. Vitamin D supplementation needs careful monitoring, as it can increase calcium absorption, potentially leading to higher urinary calcium levels in susceptible individuals.

Comparing Key Supplements for Prevention


Feature	Potassium Citrate	Magnesium Citrate
Mechanism of Action	Increases urinary citrate and pH, binds calcium in urine.	Binds oxalate in intestines and urine, inhibits crystal growth.
Primary Target Stones	Calcium oxalate, uric acid, and cystine stones.	Calcium oxalate stones.
Prescription Status	Typically prescribed by a doctor.	Often available over-the-counter.
Key Benefit	Strong evidence for reducing recurrence of multiple stone types.	Corrects hypomagnesuria and reduces oxalate absorption.
Side Effects	Can cause GI issues; requires monitoring.	Can cause laxative effects.

The Role of Lifestyle and Diet

No supplement can replace the foundational importance of lifestyle and dietary changes in kidney stone prevention. These are often the first and most effective lines of defense.

Hydration

Drink plenty of fluids: Aim for a urine output of at least 2 to 2.5 liters per day. Water is best, but other fluids like citrus juices (lemonade, orange juice) can also be beneficial as they contain citrate.

Dietary Modifications

Limit sodium: A high-sodium diet increases urinary calcium excretion. Aim for federal guidelines of under 2,300 mg daily.
Get enough dietary calcium: Paradoxically, low dietary calcium increases kidney stone risk because it leaves more oxalate unbound for absorption. Consume 1,000–1,200 mg of calcium daily from food sources like dairy.
Limit animal protein: High intake of animal protein can increase urinary calcium and uric acid. Replace some animal protein with plant-based sources like legumes.
Mind oxalate intake (if needed): While most healthy individuals don't need to strictly limit oxalate, those with very high urinary oxalate may be advised to limit foods like spinach, nuts, and rhubarb. Pairing these foods with calcium sources can help.

Conclusion: Which Supplement is Right for You?

There is no single "best" supplement for preventing kidney stones, as the most effective choice depends on the individual's specific metabolic profile and stone composition. Potassium citrate offers robust, evidence-based support for a wide range of stone formers, while magnesium citrate is particularly beneficial for calcium oxalate stones. Newer options like probiotics show promise but need further research. Crucially, supplements are an adjunct to, not a replacement for, proper hydration and dietary management. Always consult with a healthcare professional, such as a nephrologist or urologist, to determine the underlying cause of stone formation and create a personalized, safe prevention plan.

Medical and Dietary Therapy for Kidney Stone Prevention - PMC

Frequently Asked Questions

There is no single best supplement for all kidney stone types, as the ideal treatment depends on the underlying cause and stone composition. For many calcium and uric acid stone formers, potassium citrate is highly effective, but a urologist should make the recommendation after an evaluation.

Magnesium citrate helps prevent calcium oxalate stones by binding to oxalate in the intestines, reducing its absorption. In the urine, it also forms a more soluble complex with oxalate, decreasing calcium oxalate saturation.

No, you should be cautious with high-dose Vitamin C supplements. Excess ascorbic acid is metabolized into oxalate and can significantly increase urinary oxalate, thereby increasing the risk of forming calcium oxalate stones.

Dietary calcium is preferred and is protective against calcium oxalate stones because it binds to oxalate in the gut. Calcium supplements, especially when taken between meals, can increase urinary calcium and may increase stone risk.

Certain probiotics, like Oxalobacter formigenes, have shown promise by degrading intestinal oxalate, which can lower urinary oxalate levels. However, large-scale clinical trials are still needed to confirm their widespread efficacy.

Supplements alone are not sufficient to prevent kidney stones. They should be used as part of a comprehensive strategy that prioritizes high fluid intake, proper diet, and addressing underlying risk factors.

Yes, it is crucial to consult a healthcare professional, such as a urologist or nephrologist, before starting any new supplement regimen. They can identify your stone type and metabolic risk factors to recommend the most appropriate and safe treatment.

Potassium citrate increases urinary citrate and pH, benefiting several stone types, including uric acid. Magnesium citrate primarily works by binding oxalate in the gut and urine, targeting calcium oxalate stones. Potassium citrate is more commonly a prescription medication.