What Supplements Have High Oxalates? A Complete Guide

December 2, 2025 •

4 min read

According to the National Kidney Foundation, more than half a million people seek emergency care for kidney stones each year, and knowing what supplements have high oxalates can be crucial for those at risk. This guide will detail specific supplements and formulas that are known to contain significant levels of oxalate, helping you make informed decisions about your health regimen.

Quick Summary

This article outlines which dietary supplements and herbal formulas contain high levels of oxalates, a factor that can contribute to kidney stone formation. It covers common culprits like high-dose vitamin C, beetroot powder, and certain plant-based protein powders, providing guidance on how to manage intake and make safer choices.

Key Points

High-Dose Vitamin C: Supplements delivering high quantities of ascorbic acid can significantly increase urinary oxalate excretion, raising kidney stone risk.
Beetroot Powder: A concentrated source of oxalates, often used by athletes, which can quickly add to your daily oxalate intake.
Ashwagandha and Turmeric: Herbal supplements derived from high-oxalate plants, potentially increasing oxalate load depending on concentration.
Green 'Superfood' Powders: Often contain a high concentration of leafy greens like spinach and kale, which are naturally rich in oxalates.
Plant-Based Protein Powders: Those made from soy, peas, or other legumes and seeds may contain elevated levels of oxalates.
Manage with Calcium: Taking calcium with meals can help bind oxalates in the gut, reducing their absorption and potential for stone formation.

Understanding Oxalates in Supplements

Oxalates, or oxalic acid, are natural compounds found in plants and are also produced as a metabolic byproduct in the body. For most people, consuming oxalates is not a concern, but for individuals prone to calcium oxalate kidney stones, managing intake is vital. When excess oxalate is present in the urine, it can bind with calcium and form crystals that develop into painful stones. While diet is a major source, supplements—especially those derived from high-oxalate plants—can concentrate this compound, posing a hidden risk.

The Surprising High-Oxalate Culprits

Many people are aware of high-oxalate foods like spinach and rhubarb, but few realize that some seemingly healthy supplements pack a concentrated oxalate punch. This is particularly true for powders derived from plants and high-dose vitamins.

High-Dose Vitamin C (Ascorbic Acid): This is one of the most well-documented culprits. When ingested in large quantities, vitamin C is partly metabolized into oxalate. Studies have shown that supplementing with significant amounts of ascorbic acid daily can increase urinary oxalate excretion.
Beetroot Powder: Popular for athletic performance and heart health, beetroot powder is a concentrated form of a very high-oxalate vegetable. A single tablespoon of beet powder can contain a substantial amount of oxalate, which is a concern for susceptible individuals.
Ashwagandha: This adaptogenic herb, often sold in capsules, has been identified as having very high oxalate content. The Oxalosis and Hyperoxaluria Foundation lists some ashwagandha formulas with extremely high oxalate levels per serving.
Turmeric Supplements: Turmeric, or its active component curcumin, is another widely used supplement. However, turmeric root is known to contain oxalates, and concentrated supplements can deliver a higher dose than one would get from culinary use alone.
Green “Superfood” Powders: Many of these blends contain a host of high-oxalate ingredients, such as spinach, kale, and other leafy greens, in a highly concentrated powder form. This can significantly increase the total daily oxalate load without the user's knowledge.
Plant-Based Protein Powders (Soy, Hemp): Soy products are naturally high in oxalates, and soy protein powder is no exception. Similarly, hemp and other seed-based protein powders can contribute to your oxalate intake, as seeds contain significant amounts of this compound.

Comparing High-Oxalate Supplements


Supplement Category	Example Product	Typical Oxalate Concern	Who Should Be Cautious?
High-Dose Vitamin C	Ascorbic acid tablets	Metabolizes to oxalate	Individuals with a history of calcium oxalate kidney stones
Beetroot Powder	Standard beetroot powder	Highly concentrated beet source	Athletes or anyone using powder daily
Herbal Supplements	Ashwagandha, Turmeric	Derived from high-oxalate plants	Those on a low-oxalate diet or with kidney concerns
Green Superfood Blends	Spinach, kale-based powders	Concentrated leafy greens	Anyone with a genetic predisposition to hyperoxaluria
Plant Protein Powders	Soy, pea, hemp powders	Sourced from high-oxalate legumes/seeds	Vegans or vegetarians prone to stones

Strategies for Managing Oxalate Intake from Supplements

For those concerned about high-oxalate supplements, several strategies can help minimize risk while still receiving necessary nutrients.

Read Labels Carefully: Always check the ingredient list for whole-food sources of high-oxalate plants like spinach, beets, and soy. Some supplements may not disclose the oxalate content, but the presence of these ingredients is a clear indicator.
Opt for Alternative Supplements: If you need specific nutrients, consider low-oxalate alternatives. For example, instead of high-dose ascorbic acid, opt for a multi-vitamin with a lower vitamin C content or get it from food sources like oranges. Calcium citrate is often recommended as a calcium supplement for stone formers, as the citrate helps inhibit stone formation.
Timing Your Supplement Intake: Taking calcium supplements with meals can help bind oxalate in the gut, reducing its absorption into the bloodstream. However, some studies suggest that taking calcium supplements between meals may increase urinary calcium excretion and not effectively reduce oxalate.
Prioritize Hydration: Increasing your fluid intake is one of the most effective ways to prevent kidney stones. Extra fluids help flush oxalate from the kidneys, preventing it from building up and forming crystals. Aim for adequate fluid intake daily.
Consult a Professional: If you are at risk for kidney stones or have a history of them, it is always best to consult with a doctor or a registered dietitian. They can help you create a personalized plan to manage your oxalate intake from both food and supplements.

Can Calcium Supplements Increase Oxalate Absorption?

It's a common misconception that all calcium supplements are bad for those with kidney stone concerns. In fact, dietary calcium helps bind to oxalate in the intestines, preventing its absorption. However, the timing and form of calcium matter. Calcium supplements taken without food, or in certain forms like calcium carbonate, may not be as effective in binding oxalate and could potentially increase urinary calcium. For those concerned about stones, calcium citrate with a meal is generally a safer option. Discover more about calcium and oxalate management on this detailed guide from Rutgers Cancer Institute.

Conclusion

While supplements offer various health benefits, it's crucial for individuals susceptible to kidney stones to be aware of hidden oxalate content. High-dose vitamin C, beetroot powder, certain herbal extracts like ashwagandha and turmeric, and green superfood powders are among the key supplements that may contribute to a high oxalate load. By carefully reading labels, choosing lower-oxalate alternatives, timing supplements with meals, and staying well-hydrated, you can better manage your intake and reduce the risk of forming calcium oxalate kidney stones. A personalized consultation with a healthcare provider is the most reliable way to navigate your specific dietary needs.

Frequently Asked Questions

Yes, studies have shown that high-dose vitamin C can increase urinary oxalate excretion, which in turn can raise the risk of developing calcium oxalate kidney stones, especially for those who are already prone to them.

Not all, but many popular plant-based protein powders derived from soy, peas, and hemp can contain significant amounts of oxalates, as these plants are naturally high in the compound. It is best to check the ingredients if you are concerned about your oxalate intake.

Yes, taking a calcium supplement with a meal can help bind to oxalates in the digestive tract, preventing them from being absorbed into the bloodstream. However, the timing and form of the supplement are important; calcium citrate with meals is often recommended.

For those with a history of kidney stones, many experts recommend being mindful of the amount of daily vitamin C supplement intake to minimize the conversion to oxalate. The maximum recommended daily intake for adults is 2,000 mg.

Herbal supplements like ashwagandha and turmeric are derived from plant roots or leaves, which can naturally contain high levels of oxalates. When these plants are concentrated into a powdered or encapsulated form, the oxalate content can also become concentrated.

Many 'green superfood' powders contain concentrated amounts of high-oxalate ingredients such as spinach and kale. Individuals with a history of kidney stones should be cautious with these products and check the ingredient list carefully or opt for lower-oxalate alternatives.

The most effective method is to increase your fluid intake, particularly water, aiming for adequate daily intake. This helps dilute the urine and flushes oxalates and other minerals from your kidneys before they can form crystals.