Introduction

Beyond how much urine you produce and what’s in it, there’s another often-overlooked factor that could be contributing to your stones: your urine pH! More than just a number, it’s an important determinant of your stone type1, so join us as we explore the simple changes that could shift the balance in your favor.

What is urine pH? Why does it matter for kidney stone formers?

Urine pH measures how alkaline or acidic your urine is, on a scale from 0 to 14. A reading of 7 – right in the middle – means that your urine is neither acidic nor alkaline.  For example, pure water has a pH of 7.  Any reading below 7 is acidic, while any reading above 7 means it’s alkaline.

Your urine pH may determine whether minerals stay dissolved or combine to form crystals that grow into kidney stones. For example, when urine pH falls below 5.52, uric acid in your urine is more likely to form crystals. Over time, these crystals can accumulate and develop into uric acid stones!

Furthermore, a lower urine pH can also contribute to calcium oxalate and cystine stone formation. If you’re prone to forming these stones, raising your urine pH may help prevent new ones3,4!

Does it mean that having a higher urine pH is always better?

Unfortunately, that’s not the case! While raising your urine pH may be associated with certain types of stones, having a urine pH that’s too high can backfire. Struvite (usually associated with infections) and calcium phosphate stones (often caused by other medical conditions) tend to form in more alkaline conditions – especially when urine pH exceeds 75,6.

Besides, an abnormally high urine pH (pH>8) could also signal underlying conditions like urinary tract infections, acidosis, and even kidney failure7! Ideally, your urine pH should stay between 6.0 and 7.58.

Who should be most concerned about urine pH?

Not all stones are created equal – and neither is the role of urine pH in their formation! When it comes to calcium oxalate stones, urine pH usually isn’t the main concern5. Other factors like fluid intake, dietary calcium and sodium levels tend to play a bigger role!

Pay attention to your urine pH if you’re prone to forming uric acid, cystine, or calcium phosphate stones1. These stones may be associated with changes in urine pH. That said, monitoring urine pH alone isn’t enough, especially if you’re dealing with recurrent stones. Underlying factors like genetics, metabolic conditions, gastrointestinal issues, and how your body processes food can all contribute to why you’re forming stones in the first place.

That’s why your doctor may recommend additional testing — such as a 24-hour urine collection, metabolic evaluations, or even genetic screening — to get a full picture of what’s going on. These tests will provide crucial insights for a stone prevention plan that’s unique to you!

Will drinking alkaline water help to increase my urine pH?

Alkaline water is exactly what it sounds like: water with a higher pH than regular water (pH 7). Depending on their mineral content, most store-bought options have a pH between 8 and 10. However, drinking alkaline water won’t necessarily make your urine more alkaline9!

To raise urine pH effectively, you should focus on having foods with a higher alkali load –the amount of alkali your body produces after digesting certain foods. And remember, just because something is more alkaline doesn’t mean it provides a higher alkali load. It all depends on how your body processes it!

For instance, although alkaline water has a higher pH, it provides a negligible alkali load. That means it cannot produce enough alkalizing compounds to increase your urine pH effectively. Plus, your stomach is highly acidic, with a pH of 1.5-2.010. Any alkaline water consumed will likely be neutralized once it reaches your stomach11. Drinking water (about 2 liters or 67-68 oz), however, is still important. 

So what can I eat or drink to increase my urine pH?

Unfortunately, it’s not always as simple as changing what’s on your plate. Even with the same diet, people can react very differently – what works for one might not work for another. And if you’re dealing with underlying conditions, dietary changes alone may not be enough to raise your urine pH effectively.

In these cases, a more tailored approach is often needed. You might require specific medications or targeted dietary adjustments. That’s why working closely with your doctor or a registered dietitian is so important!

No matter the type of stones you form, be sure to drink plenty of fluids – especially water. Just be careful of the beverage you pick, some options like soda and energy drinks may actually increase your stone risks or lead to dehydration!12 Whenever you’re doubt of what to drink, check with your doctor.

Which medications are commonly used to increase urine pH?

Your doctor may prescribe supplements like potassium citrate. A Duke University Medical Center study involving 1480 recurrent stone formers found that long-term potassium citrate therapy (over 6 months) increased urine pH from 5.9 to 6.5, and reduced stone formation rates by 93%13!

If potassium citrate alone isn’t enough, your doctor may also recommend allopurinol, especially for uric acid stone formers. This medication prevents the breakdown of purines, which lowers the amount of uric acid in your urine and increases urine pH14.

If you’re struggling with recurrent kidney stones, speak to your doctor to determine if any of these options are right for you!

Conclusion

Urine pH is an important factor to consider when it comes to stone prevention, but it’s only part of the picture. A 24-hour urine test can pinpoint other factors contributing to your stones, helping you create a comprehensive plan to stop them from making an unwanted comeback!

References

  1. Urinary pH and stone formation. (2010). PubMed. https://pubmed.ncbi.nlm.nih.gov/21170875/#:~:text=The%20formation%20of%20various%20types,uric%20acid%20or%20cystine%20stones
  2. Kc, M., & Leslie, S. W. (2023). Uric acid nephrolithiasis. StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK560726/
  3. Manissorn, J., Fong-Ngern, K., Peerapen, P., & Thongboonkerd, V. (2017). Systematic evaluation for effects of urine pH on calcium oxalate crystallization, crystal-cell adhesion and internalization into renal tubular cells. Scientific Reports, 7(1). https://doi.org/10.1038/s41598-017-01953-4
  4. Leslie, S. W., Sajjad, H., & Nazzal, L. (2023). Cystinuria. StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK470527/
  5. Carvalho, M. (2018). Urinary pH in calcium oxalate stone formers: does it matter? Brazilian Journal of Nephrology, 40(1), 6–7. https://doi.org/10.1590/1678-4685-jbn-2018-00010002
  6. Struvite and triple phosphate renal calculi. (2025, January 1). PubMed. https://pubmed.ncbi.nlm.nih.gov/33760542/
  7. Urine pH test. Mount Sinai Health System. (n.d.). https://www.mountsinai.org/health-library/tests/urine-ph-test
  8. Leslie, S. W., Sajjad, H., & Bashir, K. (2024). 24-Hour urine testing for nephrolithiasis: interpretation and treatment guidelines. StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK482448/ – :~:text=Optimal levels,-Normal 24-hour&text=Optimal 24-hour urinary pH,and 7 for stone dissolution
  9. Piedras, P., Cumpanas, A. D., McCormac, A., Lavasani, S. a. M., Gorgen, A. R. H., Rojhani, A., Vu, M., Bhatt, R., Asplin, J., Tano, Z. E., Landman, J., Clayman, R. V., & Patel, R. M. (2024). Alkaline water: help or hype for uric acid and cystine urolithiasis? The Journal of Urology, 211(2), 276–84. https://doi.org/10.1097/ju.0000000000003767
  10. Fujimori, S. (2020). Gastric acid level of humans must decrease in the future. World Journal of Gastroenterology, 26(43), 6706–6709. https://doi.org/10.3748/wjg.v26.i43.6706
  11. LeWine, H. E. (2024). Is alkaline water better? Harvard  Health. https://www.health.harvard.edu/staying-healthy/is-alkaline-water-better
  12. Ferraro, P. M., Taylor, E. N., Gambaro, G., & Curhan, G. C. (2013). Soda and other beverages and the risk of kidney stones. Clinical Journal of the American Society of Nephrology, 8(8), 1389–1395. https://doi.org/10.2215/cjn.11661112
  13. Robinson, M. R., Leitao, V. A., Haleblian, G. E., Scales, C. D., Chandrashekar, A., Pierre, S. A., & Preminger, G. M. (2009). Impact of Long-Term Potassium citrate therapy on urinary profiles and recurrent stone formation. The Journal of Urology, 181(3), 1145–1150. https://doi.org/10.1016/j.juro.2008.11.014
  14. Qurie, A., Preuss, C. V., & Musa, R. (2023). Allopurinol. StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK499942/

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