What supplements make kidney stones worse?

November 14, 2025 •

4 min read

According to the National Kidney Foundation, approximately one in ten people will experience a kidney stone in their lifetime. For those with a history of stones, it is especially important to understand what supplements make kidney stones worse, as some common health products can increase recurrence risk.

Quick Summary

Certain supplements, such as high-dose vitamin C, excessive or improperly timed calcium, high-dose vitamin D, and specific herbal powders, can increase the risk of kidney stone formation by elevating levels of urinary calcium, oxalate, or protein.

Key Points

High-Dose Vitamin C: Supplements delivering more than 1,000 mg of vitamin C per day can increase the body's production of oxalate, raising the risk of calcium oxalate kidney stones.
Calcium Supplements: Taking calcium supplements improperly, such as on an empty stomach, can increase urinary calcium and stone risk, whereas dietary calcium is typically protective.
Excessive Vitamin D: High doses of vitamin D supplementation can lead to hypercalcemia and increased urinary calcium, which contributes to stone formation, particularly in susceptible individuals.
Oxalate-Rich Herbs: Herbal supplements, including those containing turmeric and cinnamon, can be very high in oxalate, increasing the risk for calcium oxalate stones.
Creatine and Protein Powder: Excessive intake of high-protein diets and creatine supplements can place an extra strain on the kidneys and may increase the risk of uric acid stone formation.
Timing Matters: If medically necessary, take calcium supplements with meals to ensure it binds with dietary oxalate and minimizes its impact on stone risk.
Hydration is Key: Always maintain high fluid intake to dilute urine and flush out stone-forming minerals, regardless of other supplement intake.

Understanding Kidney Stone Formation

Kidney stones are hard deposits of minerals and salts that form inside your kidneys. The most common type is a calcium oxalate stone, formed when calcium and oxalate combine in the urine. Uric acid stones are another type, influenced by high levels of uric acid. While diet and hydration are key factors, supplements can also play a significant, and often overlooked, role in either preventing or promoting stone formation. The timing and dose of certain supplements are crucial considerations.

The Surprising Risks of High-Dose Vitamin C Supplements

While vitamin C is an essential nutrient found naturally in many fruits and vegetables, high-dose supplements are another matter entirely. Studies have found a link between high-dose vitamin C supplements and an increased risk of kidney stones, particularly in men. This is because the body metabolizes large doses of supplemental vitamin C (over 1,000 mg/day) into oxalate. This excess oxalate is then excreted in the urine, where it can bind with calcium to form painful calcium oxalate stones. Vitamin C from food, however, is absorbed differently and does not carry the same risk. The recommended dietary allowance is much lower than the amounts found in many supplements, making it a key supplement to monitor.

The Controversy Around Calcium and Vitamin D Supplements

For years, those prone to kidney stones were advised to limit dietary calcium, but research has shown this to be harmful to bone health and ineffective at preventing stones. In fact, adequate dietary calcium is important because it binds with oxalate in the gut, preventing its absorption. However, the use of supplemental calcium requires more caution, especially in specific scenarios.

Incorrect Timing: Calcium supplements taken between meals or on an empty stomach can increase urinary calcium, raising the risk of stones. Taking supplemental calcium with meals allows it to bind with oxalate in the digestive tract, a protective mechanism.
Excessive Intake: Excessive intake of both supplemental calcium and vitamin D can lead to higher levels of calcium in the blood and urine, increasing stone risk.
Vitamin D Interaction: Vitamin D facilitates the intestinal absorption of calcium. While this is necessary for bone health, too much supplemental vitamin D, especially when combined with calcium supplements, can push urinary calcium levels higher.

Oxalate-Rich Herbal and 'Superfood' Powders

Many popular wellness supplements, particularly herbal powders and 'green superfood' blends, can be surprisingly high in oxalate. Oxalate is a natural compound found in many plant foods that can bind with calcium to form stones. For individuals with a history of calcium oxalate stones, these supplements can significantly increase their oxalate load. Examples of high-oxalate ingredients often found in these products include:

Turmeric
Cinnamon
Spinach
Rhubarb
Soy products

The Impact of Creatine and High-Protein Supplements

Bodybuilders and athletes often turn to creatine and high-protein powders to enhance performance and muscle growth. However, excessive consumption can be problematic for the kidneys. High-protein diets can increase the production of uric acid and a larger acid load for the kidneys, which can contribute to the formation of uric acid stones. Creatine, a substance that helps muscles make energy, can place extra stress on the kidneys, especially in individuals with pre-existing kidney disease. High levels of creatine can also raise blood levels of creatinine, a waste product, which can be mistakenly interpreted as worsening kidney function.

A Comparison of Common Supplements and Kidney Stone Risk


Supplement Type	Risk Factor	Mechanism of Action	Recommended Action for Stone-Formers
High-Dose Vitamin C	Increases oxalate	Converts to oxalate in the body, which binds to calcium	Avoid large doses (>1000 mg/day) and prioritize dietary sources.
Calcium Supplements	Improper timing/excess	Increases urinary calcium levels, particularly when taken alone	Take with meals to bind dietary oxalate; prefer dietary calcium.
High-Dose Vitamin D	Excessive intake	Increases calcium absorption, potentially raising urinary calcium	Monitor intake and blood levels; avoid excessive doses.
Creatine	High intake	Can place additional stress on kidneys	Consult a doctor before use, especially with pre-existing kidney conditions.
Oxalate-Rich Herbs	High oxalate content	Increases overall oxalate load, leading to more calcium-oxalate	Avoid supplements known to be high in oxalate (e.g., turmeric, cinnamon).

Mitigating Kidney Stone Risk from Supplements

Talk to a Doctor: Before starting any new supplement, especially if you have a history of kidney stones, consult a healthcare provider or nephrologist. They can help you understand the risks and determine if a supplement is right for you. They may also recommend tests to determine your stone composition.
Prioritize Diet over Supplements: For most nutrients, including calcium and vitamin C, obtaining them from a balanced diet is safer and more effective. For example, calcium in milk or yogurt is protective, while supplemental calcium can be risky.
Read Labels Carefully: Be aware of hidden high-risk ingredients. Look for excessive doses of vitamins, or herbal ingredients known to be high in oxalate.
Stay Hydrated: Drinking plenty of water is arguably the most important preventative measure for all types of kidney stones. It helps dilute stone-forming substances in the urine, making crystallization less likely.

Conclusion

For individuals with a history of kidney stones, navigating the world of supplements requires careful consideration. While many supplements are beneficial for general health, certain types and dosages of vitamin C, calcium, vitamin D, and herbal powders can significantly increase the risk of stone formation or recurrence. The key takeaway is to prioritize getting nutrients from a balanced diet, consult with a healthcare professional before taking new supplements, and ensure adequate hydration to mitigate risk. Taking a proactive and informed approach to supplementation can help prevent a painful recurrence. For more information on prevention strategies, consult authoritative sources like the National Kidney Foundation.

Frequently Asked Questions

Standard multivitamins typically don't contain high enough doses of problematic nutrients to pose a significant risk, unlike high-dose individual supplements. However, it's wise to check the label for extremely high amounts of vitamin C or D and discuss it with your doctor.

No, you should not avoid all calcium. Restricting dietary calcium is actually linked to an increased risk of stones because it allows more oxalate to be absorbed by the body. The issue lies primarily with calcium supplements, especially when taken incorrectly.

The body processes high-dose supplemental vitamin C differently than the vitamin C from food sources. In high supplemental amounts, it's metabolized into oxalate, which can then form crystals. The vitamin C from food is absorbed more efficiently and poses a negligible risk.

Yes, but with caution and medical supervision. Moderate doses of vitamin D are generally safe, but excessive intake, particularly when combined with supplemental calcium, can increase urinary calcium. Your doctor can help determine the right dose for your needs.

Turmeric, like spinach and rhubarb, is naturally high in oxalate. For those susceptible to calcium oxalate stones, taking concentrated turmeric supplements can significantly increase your oxalate intake, thereby raising your stone risk.

Excessive intake of high-protein supplements, like protein powder, or creatine can increase the load on your kidneys. This can promote the formation of uric acid stones or worsen kidney function in those with pre-existing conditions. Always consult a doctor before using them.

While critical for prevention, hydration alone may not be enough if you are taking supplements known to increase stone risk. It dilutes the urine, but reducing or modifying intake of problematic supplements like high-dose vitamin C or improperly timed calcium is also necessary.