Yes, chaga contains oxalic acid — a lot of it.

More of it than almost anything else you could reasonably put in a cup. Most chaga brands would rather you didn’t know this, but we built our entire process to account for it.

Raw chaga is one of the highest-oxalate foods known, and a small number of published cases have linked heavy, long-term use of raw chaga powder to serious kidney injury. Every traditional form of chaga, tea, powder, and capsules passes that oxalate straight to the person drinking it.

BOOM Chaga does not. Our process removes the oxalic acid, and independent lab testing finds no detectable oxalate in the finished product. It’s the same wild-harvested chaga and the same compounds people have prized for centuries, without the one thing that made drinking it every day a question worth asking.

New to chaga entirely? Start with “What is Chaga?” If you are here because you found kidney studies, keep reading.

What is Chaga?
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What Is oxalic acid (and oxalate)?

Oxalic acid is a natural compound produced by many plants and fungi. Once it’s in food or in your body, it exists as a salt called  oxalate, and the two words get used more or less interchangeably.

You have almost certainly eaten some today. Oxalates are in spinach, rhubarb, beets, almonds, and black tea. This is ordinary plant chemistry, not a contaminant or an additive.

Why the kidneys are the only exit:

  • Oxalate binds to calcium, and your body has no way to break it down. Oxalate binds to calcium, and your body has no way to break it down.
  • Anything absorbed into the bloodstream has to be filtered by the kidneys and excreted in urine. There is no other route out. Anything absorbed into the bloodstream has to be filtered by the kidneys and excreted in urine. There is no other route out.
  • At normal dietary levels, that system handles it easily. The question is what happens when the load goes up tenfold and stays there for years. At normal dietary levels, that system handles it easily. The question is what happens when the load goes up tenfold and stays there for years.
Does chaga contain oxalates?

Chaga contains oxalates at levels that place it in a category of its own. This is the part of the chaga conversation that mostly does not happen.

Chaga's benefits get discussed endlessly, but its oxalate content, arguably the most remarkable number attached to the organism, tends to be ignored.
How much oxalate is in chaga?

When researchers analyzed the chaga powder behind a documented Korean case of kidney failure, it measured 14.2 grams of oxalate per 100 grams.

14.2 g oxalate per 100 g of powder

That is roughly 14% oxalate by weight, and about fifteen times the oxalate density of raw spinach.

Content varies, too. Chaga is wild, and as we cover in “What is Chaga?”, the conk draws its chemistry straight out of one particular birch in one particular forest. Published figures differ between samples. Almost nothing on the market is tested for oxalate at all, and if a label does not report a number, nobody measured one.

What is Chaga?

Why tea, powder, and capsules pass it straight to you

Oxalate is water-soluble.

That means it dissolves into your brew alongside everything you actually want.
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Tea and decoctions

pull the beneficial compounds and the oxalate into the same cup.

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Raw powder

delivers the entire load because nothing has been separated out.

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Capsules

of ground conk do the same thing in a smaller package.
None of these methods separates the two. None of them were designed to. That is the problem we set out to solve, and solving it is the whole reason BOOM Chaga looks the way it does.
Chaga and kidneys: how oxalate can cause damage

Oxalate itself is not the problem. The problem is what happens when more of it arrives than the kidneys can clear, and when that continues for long enough to do lasting harm.
What is oxalate nephropathy?

Oxalate nephropathy is a kidney injury caused by oxalate crystals accumulating in kidney tissue.

The mechanism is straightforward. When more oxalate arrives than the kidneys can clear, calcium oxalate crystals form and lodge in the filtering tubules, rather than being washed out. The crystals cause injury and inflammation, and if sustained long enough, that damage can become permanent.

This is not a chaga-specific phenomenon. Secondary oxalate nephropathy is a recognized clinical condition documented after bariatric surgery, in fat-malabsorption disorders, and with very high-dose vitamin C, which the body partly converts into oxalate. Chaga is one recognized dietary trigger among several.

The documented cases

Three published case reports of chaga oxalate nephropathy form the entire basis of the concern. All three are worth knowing about, and all three involve intakes far beyond a normal serving.

Kikuchi and colleagues, 2014

The first reported case was published in Clinical Nephrology. A patient took chaga powder daily for approximately six months, and a biopsy revealed calcium oxalate crystals in kidney tissue.

Lee and colleagues, 2020

Published in the Journal of Korean Medical Science. This is the case where the powder itself was analyzed and returned the 14.2 gram figure. The patient progressed to end-stage renal disease and required dialysis after sustained daily use.

Kwon and colleagues, 2022

Published in Medicine. Acute kidney injury in a patient taking roughly 10 to 15 grams of chaga powder daily alongside vitamin C, a combination that raises oxalate load from two directions at once.

What the pattern actually tells us

Three cases across a decade do not constitute an epidemic, and reading it as one would be a mistake. Enormous numbers of people have taken chaga for years without incident, which is exactly what centuries of daily use across Siberia and Northern Europe would predict.

But case reports are how dose-dependent problems get found, and the pattern here is consistent and specific. Raw powder. High daily doses sustained for months or years, sometimes stacked with vitamin C.

They do show a consistent pattern worth paying attention to:
Raw powder.
Large daily doses.
Sustained use over months or years.
That pattern is the risk, and it is solvable.

It is not an argument against chaga.

It is an argument for paying attention to how chaga is made.

Who’s most at risk?

Oxalate is a dose-and-duration problem, so the risk concentrates in a few specific situations. It’s worth extra caution, and a conversation with your doctor, if any of these describe you:

Existing kidney disease

Less filtering capacity means less margin for an unusual load.

A history of kidney stones

Roughly 8 in 10 stones are calcium oxalate. If you have formed one, your body has already shown it tends to crystallize oxalate.

High-dose vitamin C

Your body converts part of it into oxalate. This is the exact combination behind the 2022 case.

Large doses or years of daily use

The two variables that matter, moving the wrong way together.

Chronic underhydration

Concentrated urine is where crystals form, and this is the one factor almost anyone can improve today.

Conditions affecting fat absorption

Including Crohn's disease, celiac disease, and a history of bariatric surgery, all of which increase the amount of oxalate absorbed from the gut.

If none of that applies to you, you are in the group for whom chaga is generally well tolerated. If some of it does, that is a conversation for your doctor, not a product page. We would rather you ask than guess.

How BOOM Chaga removes oxalic acid

Everything above is the problem. Here is our answer to it.

Oxalate-free and independently verified

Anyone can say they removed the oxalate.

You cannot taste it, see it, or infer it from a good sourcing story. It has to be measured in a lab by someone with no stake in the answer. BOOM Chaga is tested by an independent third-party laboratory before release, and the oxalate result comes back the same way: none detected.

That is what oxalate-free means on our packaging. Not a reduction, not a marketing adjective, but a lab finding no oxalate in the finished product.

Heavy metals and microbials are also on the panel, though we would not call that a differentiator. Any wild-harvested ingredient should be screened for them, and as we explain in “What is Chaga?”, a conk that spent decades pulling chemistry out of a living birch does not discriminate between the compounds you want and the ones you don't. That testing is table stakes.

Oxalate is the assay almost nobody runs. It is separate, it costs more, and it is not on a standard supplement panel. It is on ours, because the claim on the front of the box is worthless without it.

Want to see the lab results? Request our current certificate of analysis, and we will send it over. A claim you can check beats a claim you cannot.

What is Chaga?

BOOM Chaga vs. raw chaga, tea, powder & capsules

Swipe or scroll to compare →

Comparison Tea or decoction Powder Capsules
Oxalate
None detected
Dissolves into your drink Full load consumed Full load consumed
Oxalate tested?
Third-party tested
No Rarely Rarely
Extraction
Water only, both fractions
Water-soluble only None, cell walls stay intact Varies, often unextracted
Dose
Single-serve, consistent
Unknown, varies by brew Approximate Stated, potency varies
Contaminant testing
Third-party tested
Depends on supplier Varies Varies
Prep time
Two seconds
2 to 8 hours Stir and hope None

Every traditional form of chaga passes the oxalate through to you. Ours was made not to. Or skip ahead and try it for yourself.

Order BOOM Chaga Today
Getting chaga’s benefits without the oxalate risk

The oxalate issue is a preparation problem, not a problem with the chaga itself.

Everything that makes chaga worth drinking is still true. The antioxidant density is genuinely exceptional. Beta-glucans are at the center of serious immune research. People across the northern forest belt called it the King of Herbs and drank it daily for centuries, and they were not wrong to.

None of that changes because of anything on this page. What changes is what you should expect from the product you buy

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What sensible daily use looks like

Whatever chaga you choose, these habits keep the oxalate question small. With BOOM Chaga, the first two are already handled.

  • Stick to one serving a day. More is not better here, and dose is half of what went wrong in every documented case. Stick to one serving a day. More is not better here, and dose is half of what went wrong in every documented case.
  • Choose an extract over raw powder for long-term daily use. All three cases involved powder. Choose an extract over raw powder for long-term daily use. All three cases involved powder.
  • Drink plenty of water. Good practice regardless, and it costs you nothing. Drink plenty of water. Good practice regardless, and it costs you nothing.
  • Watch high-dose vitamin C alongside high-oxalate foods. Your body turns part of it into more oxalate. Watch high-dose vitamin C alongside high-oxalate foods. Your body turns part of it into more oxalate.
  • Talk to your doctor first if you have kidney disease or have ever passed a stone. Talk to your doctor first if you have kidney disease or have ever passed a stone.

Disclaimer: These statements have not been evaluated by the Food and Drug Administration. BOOM Chaga is not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary. Consult your healthcare provider before adding any functional beverage to your routine, especially if you are pregnant, nursing, taking medication, or managing a kidney or other health condition.

Do that, and chaga becomes what it has always been: a daily cup, not a calculation.

Read next: The benefits of chaga, and what the research actually supports

Benefits of Chaga

FAQ
Is chaga bad for your kidneys?

Chaga is not inherently bad for your kidneys, but it is extremely high in oxalate. Three published cases have linked heavy, sustained use of raw chaga powder to kidney injury. Every documented case involved high daily doses over months or years, not a normal serving. If you have kidney disease or a history of stones, talk to your doctor before taking chaga in any form.

Does chaga cause kidney problems?

Chaga does not cause kidney problems for most healthy adults at normal servings, but at high doses over long periods, it can. The documented chaga side effects involving the kidneys all trace back to a single cause, oxalate, and all follow the same pattern of raw powder taken in large amounts for months or years. Dose and duration are the variables that matter.

What is chaga oxalate nephropathy?

Chaga oxalate nephropathy is a kidney injury caused by calcium oxalate crystals building up in kidney tissue after heavy chaga consumption. It is the mechanism behind every documented case of chaga kidney damage. It was first reported in 2014, with two further cases published in 2020 and 2022. It is a recognized form of secondary oxalate nephropathy, the same condition documented after bariatric surgery and high-dose vitamin C.

How much oxalate is in chaga?

Chaga is one of the highest-oxalate foods known. A powder analyzed in a 2020 Korean case report contained 14.2 grams of oxalate per 100 grams, roughly fifteen times the oxalate density of raw spinach. Content varies between wild samples, and most chaga products are never tested for it.

Can chaga cause kidney stones?

Chaga may plausibly contribute to kidney stone risk, as roughly 8 in 10 stones are composed of calcium oxalate, and chaga is exceptionally oxalate-dense. No published case has specifically attributed a stone to chaga, but the mechanism is the same as that behind standard advice to watch high-oxalate foods if you are a stone former. Staying well hydrated and eating calcium with meals both help.

Is chaga safe if I have had kidney stones?

If you have had a kidney stone, ask your doctor before taking chaga. A previous calcium oxalate stone means your body has already shown a tendency to crystallize oxalate, which makes a very high-oxalate ingredient worth a professional opinion. That is not a call we can make for you, no matter the product.

Does brewing or boiling chaga remove the oxalates?

No, and boiling works against you here. Oxalate is water-soluble, so simmering it pulls it directly into the tea alongside the compounds you want. With vegetables, you can boil and discard the water, but with chaga tea, the water is the product. Longer brewing means more of everything, oxalate included. You cannot brew your way to a low-oxalate chaga, let alone an oxalate-free chaga. That takes a separation step no home method can perform.

Is BOOM Chaga oxalate-free?

Yes. An independent third-party lab tests the finished product before release and finds no detectable oxalate. That is the whole reason the process exists, and it is why we are comfortable putting oxalate-free on the box. We have not found another chaga product that can say the same. We will share the certificate of analysis with anyone who asks for it.

First time here?

See “What is Chaga?” or the “Benefits of Chaga.”

What is Chaga? Benefits of Chaga

Footnotes:

  1. Kikuchi Y, Seta K, Ogawa Y, et al. Chaga mushroom-induced oxalate nephropathy. Clinical Nephrology. 2014;81(6):440–444.
  2. Lumlertgul N, Siribamrungwong M, Jaber BL, Susantitaphong P. Secondary oxalate nephropathy: a systematic review. Kidney International Reports. 2018;3(6):1363–1372.
  3. Lee S, Lee HY, Park Y, et al. Development of end stage renal disease after long-term ingestion of chaga mushroom: case report and review of literatures. Journal of Korean Medical Science. 2020;35(19):e122.
  4. Kwon YJ, Son HS, Lee SM, et al. Chaga mushroom-induced oxalate nephropathy that clinically manifested as nephrotic syndrome. Medicine. 2022;101(11):e28997.
  5. A brief overview of the medicinal and nutraceutical importance of Inonotus obliquus (chaga) mushrooms. Heliyon. 2024.