Celiac Disease and Supplements: Do Mushroom Extracts Contain Gluten?

If you live with celiac disease — an autoimmune disease of the small intestine triggered by gluten — you ask one question about every dietary supplement before any other, including extracts of medicinal mushrooms such as reishi (Ganoderma lucidum, the lingzhi of Chinese medicine) and lion’s mane: is there gluten in it? The honest answer: as far as we found, no medicinal mushroom has been tested in people with celiac disease, and we have not sent our extracts for gluten testing. What was measured in them is starch — and it was not detected.

This page is built around the question you are actually asking, not around “what mushrooms do for celiac disease” — because on that there is nothing to say: a PubMed search for mushrooms, beta-glucan and celiac disease returns zero results. What does exist: a trial that established how many milligrams of gluten a day damage the gut lining, lab surveys that found gluten in shelf supplements and in medications, a study showing that “gluten-degrading” enzymes do not degrade it, surveys on brain fog, and a study showing how much celiac disease shifts the levothyroxine dose. The wider picture on autoimmune diseases is on the medicinal mushrooms and autoimmune disease page.

Is there gluten in medicinal mushroom extracts?

That depends on what is in the bottle, not on the mushroom. A mushroom is not a grain and does not make gluten — but a mushroom product can contain grain: mycelium grown on grain, fillers, or cross-contact. The real answer for any product is a gluten lab test. Our extracts have not had one, so we do not write “gluten-free”.

The confusion starts with language. “Medicinal mushrooms” sounds like one substance, but the market sells three completely different products: mycelium — the fibrous, root-like part of the fungus — grown on a grain substrate and milled together with it; imported dried fruiting body, ground into powder or extracted; and an extract of fruiting body. For celiac disease, the difference between them is not only a matter of quality but of composition: in the first product, the grain is part of the product itself.

And beyond the substrate, there is everything anyone with celiac disease already knows from every other product: processing aids, capsules, fillers, and a factory that also makes products with wheat. Those are not questions about mushrooms — they are questions about manufacturing. And because we found not a single study on mushrooms in celiac disease itself, this page deals with what was measured: how much gluten counts, where it turns up in supplements and medications, what a starch test proves and what it does not, and what about brain fog and levothyroxine.

What was measured, in which system — and what came out?

The table sorts the questions people with celiac disease ask about supplements by what was measured on them. The rows on mushrooms in celiac disease are empty. The rows on gluten in supplements and medications are full — of lab testing. And the only row about our bottle is a starch test, which is not a gluten test.

What does the mushroom grow on — and why is mycelium on grain a different question?

Because in mycelium-on-grain, the grain is part of the product. The mycelium grows through the substrate, and in these products the two are milled together. That is why their beta-glucan is usually below 7%, and most of the weight is grain starch. Whether gluten remains in them, and how much — we found no study that measured it.

What the market claims. Two reassuring claims, neither of them measured: “the mushroom digested the grain”, and “the grain is rice, so there is no problem”. The first sounds logical — fungi do break down the substrate they grow on — but being partly broken down is not the same as being gluten-free. The second is true only if it really is rice, and only if there is no cross-contact in the factory.

What exactly was measured. We searched PubMed for mycelium and gluten: 3 results — a plant-based sausage made from shiitake mycelium with wheat proteins, shiitake grown on palm residue, and reishi grown on agricultural waste. None of them measured gluten in a mycelium product. What was measured is how far a label can be trusted: in 2017 researchers tested 19 batches of reishi supplements in the US, and only 5 of them — 26.3% — matched what was written on them. And the study closest to the claim “it is already broken down” comes from a different direction: in 2015, researchers tested 5 digestive-enzyme supplements sold precisely as aids for breaking down gluten. In an ELISA test they appeared to degrade it “modestly”, but by mass spectrometry the 9 immunogenic gluten sequences stayed largely intact. In other words, partial breakdown can look good in one test and leave behind exactly what does the harm.

Why it does not carry over automatically in either direction. We found no study showing that mycelium on wheat leaves gluten behind, and none showing that it does not. What can be known today: that in such a product the grain is inside, so the question is legitimate. What to ask the manufacturer: “What grain was the mycelium grown on? Was the finished product tested for gluten, by which method, and what was the result?” — and ask for the report itself, not a sentence on the package.

What does a starch result of “not detected” prove — and what does it not prove?

It proves there is no measurable starch in the finished extract — meaning no grain in it as a material. It does not prove there is no gluten: gluten is a protein, not a starch, measured by a different test. We did not order that test. So “alpha-glucan not detected” is real data, but not clearance for celiac disease.

To understand the difference, you need to know what was measured. In 2016, researchers from the company Megazyme published a method for measuring beta-glucan in mushrooms and mycelial products: total glucan is broken down with acid, and separately, the alpha-glucan — starch and glycogen — is broken down enzymatically and measured on its own. Beta-glucan is the difference. From this — and this is our inference, not a finding of the paper — such a test should expose a mycelium-on-grain product: the grain’s starch would show up in it as alpha-glucan, in large amounts. The authors work for the company that makes the test kits, and that is worth knowing.

In the four extracts of ours that were sent to TÜV Austria, alpha-glucan was not detected. That means no measurable starch was found in the finished extract — and that is all it means; about what happened before extraction, the test is silent. What our fruiting bodies grow on is not documented on this page; if it matters to you, ask us. And it does not say anything about a trace amount of gluten protein, because the starch method does not look for protein. A gluten test is an immunological test — for example an R5-type ELISA, the method used to test the 205 products in Europe that we come to in the next chapter. We write this out explicitly, because the sentence “no grain, so no gluten” is exactly the kind of leap we are asking you not to accept from any manufacturer — including us.

And what about the alcohol in the extract — what crop is it made from?

It is the right question for any liquid extract, and most labels do not answer it. Our extracts are 32% alcohol; in a 1.4 ml daily serving that is about 0.35 g of ethanol — arithmetic on the spec, not a measurement. The source of the alcohol is not detailed on this page; if it matters, contact us and ask.

Why not simply write the source? Because every figure on this page has to stand on a document, and the documents this page rests on — the lab reports — do not deal with the source of the alcohol. It is the same rule that stopped us from writing “gluten-free”: what was not measured or documented is not written, even when it would have been convenient to write it.

Our recommendation is broader than our own product: when you check any liquid extract — of a mushroom, a plant or a vitamin — ask three questions: what is the source of the alcohol or solvent, does it contain fillers or sweeteners, and was the finished product tested for gluten. And the alcohol itself — 0.35 g a day — is worth knowing about for a different reason: it is relevant to any medication list, and anyone who avoids alcohol for any reason should know it is there.

How much gluten is “too much” in celiac disease — and what does that mean for a supplement?

The threshold is measured in milligrams a day. In a controlled trial in 49 patients, 50 mg of gluten a day for 90 days damaged the gut lining; at 10 mg the average change was small, but one patient relapsed. A 2024 review notes there is still not enough controlled data for a “safe” threshold. So every extra source counts.

The 2007 trial is still the source everyone relies on. 49 adults with biopsy-confirmed celiac disease, who had kept to the diet for at least two years and were eating less than 5 mg of gluten a day, received a daily capsule of 0, 10 or 50 mg of gluten for 90 days. The ratio of villous height to crypt depth — the measure of damage to the lining — rose by 9% on placebo, fell by 1% in the 10 mg group, and fell by 20% in the 50 mg group. The authors’ conclusion: keep incidental gluten below 50 mg a day.

A 2013 European study tested 205 gluten-free products — bread, flour, pasta — by R5 ELISA: 99.5% of them were below 20 mg per kg, and 94% below the limit of quantification. The researchers concluded that the labeled products are mostly safe, and that monitoring should focus on “other sources of contamination”. Our inference — not the authors’, who did not test supplements: supplements and medications are such sources — small, daily, and not always labeled. The 2024 review adds that there is still no controlled data that defines a safe threshold, and that ongoing symptoms and damage are common. That does not mean every drop of a supplement is dangerous; it means the question “was it tested for gluten?” is a real medical question, not excessive fussiness.

How many supplements and medications contain gluten — and what makes the difference?

Lab surveys found gluten in 23.8% of 21 shelf supplements in Romania and in 26% of herbal supplements in another study. In medications in Portugal — in 44.4% of paracetamol painkillers. And what was measured from the other side: among supplements labeled “gluten-free” and sampled by Italy’s inspection laboratory, out of 4,139 labeled products — zero non-compliance; the size of the supplement subsample was not published.

Supplements. In 2011, researchers in Romania screened 21 common supplements — vitamins, minerals, plant extracts, probiotics and propolis — and found gluten in 23.8% of them. In 2023, researchers tested herbal supplements sold specifically to people with inflammatory bowel disease — turmeric, boswellia and others — and 26% of the samples were positive for gluten. Both surveys are small, but they show that a “natural” label says nothing about gluten. On the other hand, Italy’s inspection laboratory analyzed, over ten years (2015–2024), 4,139 products already labeled “gluten-free”: average non-compliance was 0.27%, and in the dietary supplements sampled — zero; how many supplements were in that subsample, the paper does not publish. This is regulator sampling of labeled products, not proof that every manufacturer who labels also tests.

Medications. A 2025 Portuguese study screened 308 products by their leaflets, and found gluten-derived excipients in 44.4% of the paracetamol painkillers and in 8.2% of the ibuprofen products. A US hospital that built a database of 84 medications found that the most reliable way to know is to contact the manufacturer directly. And a 2021 scoping review concluded that information on gluten in medications is “still scarce”, with wide variation between countries in labeling. The pharmacist is the address; the wider list of safety questions about supplements is on the medicinal mushroom side effects page.

And supplements sold as gluten-degraders? Here the answer is clearer: in 2015, five commercial digestive-enzyme supplements left the harmful gluten sequences largely intact (some of the researchers worked for a company developing a competing enzyme). A 2020 review of probiotics and prebiotics in celiac disease found the evidence “still insufficient” to justify their use in the clinic. There is no supplement that lets you eat gluten — and that is true of mushrooms too, which have not been tested for it at all.

Brain fog in celiac disease — what was measured, and is lion’s mane relevant?

The fog is real and measured: in a survey of 1,396 respondents, 89% of people with celiac disease reported poor concentration, forgetfulness and “fogginess” after gluten exposure. On lion’s mane in celiac disease — zero studies that we found. Its cognitive trials were in mild cognitive impairment and healthy young adults, with partial results. The first step is finding the gluten source.

What was measured about the complaint. The US nationwide survey, published in 2022, included 1,143 people with celiac disease and 253 people with gluten sensitivity; 89% and 95% of them, respectively, described neurocognitive impairment after gluten. The celiac disease was self-reported by the respondents, and the survey was run together with a patient organization. In 2024, researchers in Australia developed a 12-item brain fog scale for celiac disease, in 510 participants — and the scale tracked what patients felt well, but did not correspond significantly to objective cognitive tests, which only 51 of them completed. And a 2026 cross-sectional study in 62 participants found that the newly diagnosed have more fog, a lower cognitive score and poorer sleep quality than controls, while those already on the diet sit in between. The authors themselves warn against reading this as improvement from treatment — it is a snapshot, not follow-up.

What was measured about lion’s mane. In 2009, 30 adults aged 50–80 with mild cognitive impairment took lion’s mane for 16 weeks: the score rose significantly — and fell significantly 4 weeks after stopping. In 2019, in a 12-week trial, only one test out of three improved. And in 2023, in 41 young adults, a 1.8 gram dose improved speed on one test after 60 minutes, and after 28 days subjective stress fell at p=0.051 — not significant. None of them was done in celiac disease, and none measured fog caused by gluten. What to ask the doctor: “Does my fog fit gluten exposure, a nutritional deficiency or something else — and how do we check?” And if gut symptoms continue even on a strict diet, it is worth reading the irritable bowel page as well.

And sleep. The same 2026 study found poorer sleep quality in the newly diagnosed — and “reishi for sleep” is the most common Google autocomplete for “reishi for…” in Israel. But there is not a single randomized human trial of reishi and sleep, not in celiac disease and not at all. The cleanest trial of reishi in fatigue, in 132 patients with neurasthenia, found a 28.3% reduction — versus 20.1% on placebo; the real difference is about eight points, and sleep was not measured in it. Everything that was and was not tested is gathered on the reishi for sleep page.

What happened when reishi was tested in a population with fatigue and cognitive complaints?

At the high dose, symptom severity was higher than on placebo (p=0.012); at the low dose — no change (p=0.603). That was in 2021, in a placebo-controlled, pseudo-randomized crossover trial in 29 men with Gulf War illness. This is not celiac disease and not an “autoimmune flare” — but it is the closest controlled trial to the question “can it do harm?”.

Gulf War illness is a multi-system condition of chronic fatigue, pain, cognitive complaints and a neuroinflammatory component, in soldiers who served in the Gulf War. It has no connection to gluten. We bring it up because its symptoms overlap with what is described in the previous chapter, and because it is one of the few times reishi was tested against placebo on symptoms in such a population. The design: 30 days of baseline, 30 days of placebo, 30 days of low dose and 30 days of high dose — a fixed dose order, not randomized, hence “pseudo-randomized”. The authors wrote that reishi “may worsen symptoms in some sufferers”, and in the same breath — that the results are “from a small sample and preliminary”.

What this means for you: not that reishi does harm in celiac disease — that was not tested. But that the sentence “at worst it simply won’t help” does not stand up to the data. If you start any supplement and feel worse, that is a data point — stop, and tell your doctor.

Celiac disease is autoimmune — is a mushroom that stimulates the immune system a problem?

Unknown. In healthy people, purified reishi beta-glucan for 84 days raised CD3, CD4, CD8 and NK cells versus placebo; in cancer patients, Cochrane found a 3.91% rise in CD3. That is measurable stimulation, not “balance”. What it does to the antibodies or the gut lining in celiac disease — we found nobody who measured it, and we found no report of worsening either.

In celiac disease, in most cases, there is no immunosuppressive drug to “clash” with — the treatment is the diet. So the question here is about the disease itself. In 2023, researchers in Taiwan gave purified reishi beta-glucan — not the mushroom — to healthy adults aged 18–55, double-blind, and found a rise in CD3, CD4, CD8, in the CD4/CD8 ratio and in NK cells, and a significant difference in IgA whose direction the abstract does not state. A 2016 Cochrane review found, in cancer patients, a rise of 3.91% in CD3, 3.05% in CD4 and 2.02% in CD8, with study quality “not adequate”. The direction measured is upward — and we laid it out on the medicinal mushrooms and the immune system page.

On the other hand, we found no case report of an autoimmune disease worsening after reishi, lion’s mane, cordyceps or turkey tail. And that does not prove safety either — adverse-event reporting for supplements is partial and much looser than for drugs. In celiac disease, the markers that are measured are tTG antibodies and the state of the gut lining, and we found no study that measured them after a mushroom. “Not tested” is neither “safe” nor “dangerous” — it is a data void.

Celiac disease and Hashimoto’s together — what happens to levothyroxine?

Celiac disease impairs levothyroxine absorption. In 35 Hashimoto’s patients with celiac disease, those who did not keep to the diet needed a 49% higher dose (P=0.0002); those who did reached target on the same dose after 11±3 months. The two often occur together. On levothyroxine, any change — in diet or supplement — is a reason to check TSH.

The 2012 Italian study is perhaps the most useful figure on this page. 68 Hashimoto’s patients without celiac disease reached target TSH (median 1.02) on a dose of 1.31 mcg per kg a day. Patients with atypical celiac disease — without prominent gut complaints — on the same dose and over the same time, stayed at a median TSH of 4.20. Of these, 21 who kept to a gluten-free diet reached target after 11±3 months — without raising the dose; and 14 who did not keep to it reached target only on a dose of 1.96 mcg per kg — 49% more. The authors add that malabsorption of the drug can be the first clue to undiagnosed celiac disease. A 2026 review explains that the diet usually improves absorption, but some patients continue to need a higher dose, and that a liquid formulation may help — the doctor’s decision.

What this means for a supplement: a 2025 review explains that celiac disease changes the absorptive surface of the small intestine, and recommends separating levothyroxine from interfering food or supplements by 3–4 hours. On mushrooms with levothyroxine — zero studies that we found. And a 2026 review and a genetic study from the same year (OR 1.544) confirm that celiac disease and Hashimoto’s go together. The whole absorption axis, including a case in which a shelf supplement shifted a stable TSH, is laid out on the Hashimoto’s and natural treatment page; and questions about combining supplements with medication — on the drug interactions page.

Which supplements have actually been studied as relevant in celiac disease?

Not mushrooms — filling deficiencies. A 2016 review found that a gluten-free diet tends to be low in fiber, vitamin D, B12 and folate, and in iron, zinc, magnesium and calcium. A 2017 JAMA review recommends monitoring for nutritional deficiencies. Those are blood tests and a conversation with a dietitian, and we sell none of them.

The reason is simple: when you take out wheat, you also take out a major source of fiber and vitamins, and gluten-free products are often made from refined starches and flours. The 2016 review also found more saturated fat and a higher glycemic index in this diet. That does not mean every person with celiac disease needs supplements — it means there is something to measure. The JAMA review adds a point worth knowing for anyone not yet diagnosed: celiac testing should be done before you cut out gluten, because after the switch the tests are no longer accurate. If you are considering any supplement because of fatigue or fog, these tests come first.

What we actually measure in our bottle

After a whole page on what was not tested, you deserve to know what was measured — and about what exactly. We grow the mushrooms ourselves, on a farm in the Galilee, and extract fresh fruiting body: not mycelium grown on grain, and not imported powder whose history cannot be known. What substrate our fruiting bodies grow on is not documented on this page; ask us. The mushroom goes from harvest straight to extraction, with no drying step in between; as far as we know, we are among the few in the world who work this way. The extraction is triple, and its alcohol stage runs for 7 weeks. Extraction ratios on a fresh-mushroom basis: reishi 1:3 and lion’s mane 1:2. Alcohol in the finished extract: 32%.

And the numbers are not ours to set. We sent the finished extracts for testing at TÜV Austria, and what came back is the beta-glucan percentage on a dry-matter basis — and alongside it alpha-glucan, meaning starch, which was not detected in any of them. That is the chemical proof that there is no measurable grain starch in the finished extract — about the growing stages before extraction it says nothing. To understand why that matters, it helps to know the market’s three-step ladder: mycelium grown on grain, where beta-glucan is usually below 7% and most of the weight is the grain’s starch; imported dried fruiting body, whose quality depends on who dried it and when — we explained this in fresh or dried mushroom; and fresh fruiting body from the farm, which is what we do. And on a page about celiac disease, the second part has to be said just as clearly: gluten was not tested in our extracts, and so you will not find the words “gluten-free” from us. Why beta-glucan and not “total polysaccharides” — we explained separately.

All our tests are public, and anyone who wants to read the report themselves will find our explanation of how to read a COA. That is what we know how to measure and prove about what is in the bottle. What it will do for celiac disease was not measured — so it is not written.

What this page does not say — and what we do not claim

We do not claim that our extracts are gluten-free, approved for celiac disease or safe for people with celiac disease — gluten was not tested in them. We claim one measurable thing: that alpha-glucan, meaning starch, was not detected in the four extracts tested. We do not detail the source of the alcohol or the growing substrate of the fruiting bodies here, because they do not appear in the documents this page rests on. We do not claim that mushrooms affect celiac disease, the gut lining, the antibodies or brain fog — none of them has been tested in celiac disease. We do not claim that reishi improves sleep — there is no human trial of it. We do not claim that shelf supplements are “dangerous”, nor that they are “safe” — they have been tested little, and a test of the finished product — not a label — is what answers the question. And we do not deal here with benefits, National Insurance, army service or certificates — we have no expertise in those and no sources. Under DSHEA, a dietary supplement may not claim to diagnose, treat, cure or prevent any disease. What we do say: celiac disease is diagnosed and monitored by a gastroenterologist and a dietitian; anyone taking levothyroxine or any regular medication talks to the doctor or pharmacist before any supplement, including ours.

The bottom line

Medicinal mushrooms have not been tested in celiac disease, as far as we found — not in humans and not in animals. The real question for someone with celiac disease is whether there is gluten in the bottle, and the answer for any product is a test, not a label: lab surveys found gluten in about a quarter of the shelf supplements tested; in supplements labeled “gluten-free” and sampled by the Italian inspectorate — zero, in a subsample of unpublished size. In a mycelium-on-grain product the grain is part of the product, and we found nobody who measured how much gluten remains in it. In our extracts alpha-glucan was not detected — there is no measurable starch in the finished extract; the growing substrate is not documented here — but gluten was not tested, and so we do not write “gluten-free”. The threshold that was measured is 50 mg a day, with one relapse even at 10. Brain fog is real and measured, and on lion’s mane for it there is no research. And if you also have Hashimoto’s — the diet itself shifts the levothyroxine dose, and that is the most important conversation to have with your doctor.

Frequently asked questions

Is there gluten in medicinal mushroom extracts?

A mushroom is not a grain and does not make gluten, but a mushroom product can contain grain — if it is mycelium grown on grain, if it contains fillers, or if there is cross-contact in production. The only way to know is a gluten lab test on the finished product. Ask the manufacturer whether it was tested, by which method, and ask for the report.

Were Triterra’s extracts tested for gluten?

We cannot write that, because we did not test for gluten. What was tested at TÜV Austria is beta-glucan and alpha-glucan: starch was not detected in any of the four extracts, meaning there is no measurable grain starch in the finished extract. But gluten is a protein and is measured by a different test. So — not tested, and anyone with celiac disease should weigh that with their doctor.

What is the difference between mycelium on grain and fruiting body, for celiac disease?

In mycelium-on-grain, the grain is milled together with the mycelium and is part of the product; that is why it usually has a lot of starch and below 7% beta-glucan. In a fruiting-body extract, grain is not an ingredient. But fruiting body is not automatic clearance either — fillers and cross-contact in production remain a question, and the answer is a test.

Can the alcohol in the extract contain gluten?

It is a legitimate question for any liquid extract, and most labels do not answer it. Our extracts are 32% alcohol, about 0.35 g of ethanol in a 1.4 ml daily serving — arithmetic on the spec, not a measurement. We have not detailed the source of the alcohol on this page, because it does not appear in the testing documents; if it matters to you, contact us and ask.

How much gluten harms someone with celiac disease?

In a controlled trial in 49 patients, 50 mg of gluten a day for 90 days damaged the gut lining, and at 10 mg one patient relapsed. The conclusion was to keep incidental gluten below 50 mg a day. A 2024 review notes there is still not enough controlled data for a “safe” threshold, so every extra source counts.

I have celiac disease and Hashimoto’s — what about a supplement alongside levothyroxine?

Celiac disease itself impairs levothyroxine absorption: in patients who did not keep to the diet, a 49% higher dose was needed. We found no studies on mushrooms alongside levothyroxine; one 2025 review recommends separating the drug from interfering food or supplements by 3–4 hours, and the others speak of separation without a number. Any new supplement or change in diet is a reason to check TSH with your doctor.

Does lion’s mane help with brain fog in celiac disease?

That has not been tested. Lion’s mane’s cognitive trials were done in 30 adults with mild cognitive impairment and in 41 healthy young adults, with partial results — and none of them in celiac disease. Brain fog in celiac disease is most often linked to gluten exposure, so the first step is to look for the source and check for deficiencies, with your doctor.

Which supplements are actually relevant in celiac disease?

What has been studied is filling deficiencies: a gluten-free diet tends to be low in fiber, vitamin D, B12 and folate, and in iron, zinc, magnesium and calcium. These are checked with blood tests and supplemented as directed by a doctor and dietitian — and only with products that have been tested for gluten. We sell none of these.

Scientific sources (peer-reviewed)

• 49 adults with celiac disease, a daily capsule of 0, 10 or 50 mg of gluten, 90 days: villous height/crypt depth ratio +9% on placebo, −1% at 10 mg, −20% at 50 mg; one clinical relapse at 10 mg; keep below 50 mg a day — Catassi C, et al. The American Journal of Clinical Nutrition, 2007. View on PubMed
• 205 gluten-free products in 4 countries, R5 ELISA: 99.5% below 20 mg per kg, 94% below the limit of quantification; monitoring should focus on other sources of contamination — Gibert A, et al. The American Journal of Clinical Nutrition, 2013. View on PubMed
• Review: a lack of controlled data for a safe gluten threshold; ongoing symptoms and damage are common; no registered drug for celiac disease — Tye-Din JA. JGH Open, 2024. View on PubMed
• JAMA review: celiac disease as a systemic disease; test before switching to a gluten-free diet; monitor for nutritional deficiencies — Leonard MM, et al. JAMA, 2017. View on PubMed
• 21 dietary supplements from the Romanian market, immunochromatographic assay: gluten in 23.8% — Oancea S, et al. Roumanian Archives of Microbiology and Immunology, 2011. View on PubMed
• Herbal supplements for people with inflammatory bowel disease, ELISA: 26% positive for gluten — Amidžić Klarić D, et al. Pharmaceuticals (Basel), 2023. View on PubMed
• 4,139 products labeled “gluten-free”, Italy 2015–2024: average non-compliance 0.27%; zero in the dietary supplements sampled (subsample size not published); inspection-laboratory sampling of products already labeled — Giugliano R, et al. Foods, 2026. View on PubMed
• A gluten database of 84 medications: existing sources are incomplete; the reliable route is to contact the manufacturer directly — Cruz JE, et al. American Journal of Health-System Pharmacy, 2015. View on PubMed
• 308 products in Portugal: gluten-derived excipients in 44.4% of paracetamol painkillers and 8.2% of ibuprofen products — Figueiredo A, et al. Scientific Reports, 2025. View on PubMed
• Scoping review, 13 studies: wide variation between countries in gluten labeling of medications; information still scarce — Lizano-Díez I, et al. Systematic Reviews, 2021. View on PubMed
• 5 commercial digestive-enzyme supplements: the 9 immunogenic epitopes stayed largely intact; “ineffective”. Some authors from a competing company — Janssen G, et al. PLoS One, 2015. View on PubMed
• Probiotics and prebiotics in celiac disease: the evidence is still insufficient for clinical use — Marasco G, et al. Nutrients, 2020. View on PubMed
• A method for measuring beta-glucan in mushrooms and mycelial products: alpha-glucan (starch and glycogen) measured separately, beta-glucan = the difference. Authors from Megazyme — McCleary BV, Draga A. Journal of AOAC International, 2016. View on PubMed
• 19 batches of reishi supplements in the US: only 5 (26.3%) matched the label — Wu DT, et al. Scientific Reports, 2017. View on PubMed
• Nationwide survey, 1,396 respondents: 89% of people with celiac disease and 95% of the gluten-sensitive reported neurocognitive impairment after gluten. Self-reported celiac disease — Edwards George JB, et al. Journal of Clinical Gastroenterology, 2022. View on PubMed
• A brain fog scale for celiac disease, 12 items, 510 participants; did not correspond significantly to cognitive tests, which 51 completed — Knowles SR, et al. Alimentary Pharmacology & Therapeutics, 2024. View on PubMed
• Cross-sectional, 62 participants: newly diagnosed — more fog, lower cognitive score and sleep quality than controls; “not to be read as improvement from treatment” — Altinsoy C, et al. Nutrients, 2026. View on PubMed
• 30 adults aged 50–80 with mild cognitive impairment, lion’s mane for 16 weeks: the score rose — and fell 4 weeks after stopping. Not celiac disease — Mori K, et al. Phytotherapy Research, 2009. View on PubMed
• Lion’s mane for 12 weeks: only one test out of three improved — Saitsu Y, et al. Biomedical Research (Tokyo), 2019. View on PubMed
• 41 young adults: 1.8 grams — faster Stroop after 60 minutes; after 28 days subjective stress p=0.051, not significant — Docherty S, et al. Nutrients, 2023. View on PubMed
• 132 patients with neurasthenia, reishi polysaccharide 1,800 mg three times a day, 8 weeks: fatigue −28.3% versus −20.1% on placebo. Not celiac disease — Tang W, et al. Journal of Medicinal Food, 2005. View on PubMed
• 29 men with Gulf War illness, placebo-controlled crossover, pseudo-randomized (fixed dose order): low-dose reishi — no change (p=0.603); high dose — higher symptom severity (p=0.012); “small sample, preliminary” — Younger J, et al. International Journal of Environmental Research and Public Health, 2021. View on PubMed
• Purified reishi beta-glucan (not the mushroom), healthy adults aged 18–55, 84 days, double-blind: a rise in CD3, CD4, CD8, the CD4/CD8 ratio and NK cells; a significant difference in IgA, direction not stated — Chen SN, et al. Foods, 2023. View on PubMed
• Cochrane, reishi in cancer patients: CD3 +3.91%, CD4 +3.05%, CD8 +2.02%; study quality “not adequate” — Jin X, et al. Cochrane Database of Systematic Reviews, 2016. View on PubMed
• 35 Hashimoto’s patients with celiac disease: on the same dose, median TSH 4.20 versus 1.02; 21 on the diet reached target after 11±3 months without raising the dose; 14 not on the diet — a 49% higher dose (P=0.0002) — Virili C, et al. Journal of Clinical Endocrinology & Metabolism, 2012. View on PubMed
• Levothyroxine absorption in celiac disease: the diet usually improves it, some still need a higher dose; a liquid or softgel formulation may help — Saad M, Maisch NM. Annals of Pharmacotherapy, 2026. View on PubMed
• Levothyroxine — a narrow therapeutic index; celiac disease, atrophic gastritis and Helicobacter impair absorption; monitor TSH while they are treated — Skelin M, et al. Clinical Therapeutics, 2017. View on PubMed
• Celiac disease changes the absorptive surface of the small intestine; separate levothyroxine from interfering food or supplements by 3–4 hours. Authors from a pharmaceutical company — Mana DL, Rizzo LFL. Medicina (B Aires), 2025. View on PubMed
• Celiac disease and Hashimoto’s “often occur together”; targeted celiac screening recommended in selected Hashimoto’s patients — Fan X, et al. Frontiers in Endocrinology, 2026. View on PubMed
• Mendelian randomization: Hashimoto’s raises the risk of celiac disease (OR 1.544) — Pu YH, et al. British Journal of Nutrition, 2026. View on PubMed
• Gluten-free diet and deficiencies: low in fiber, vitamin D, B12, folate, iron, zinc, magnesium and calcium — Vici G, et al. Clinical Nutrition, 2016. View on PubMed

Read next

• Medicinal mushrooms and autoimmune disease — the full picture
• Hashimoto’s and natural treatment — and what is allowed with levothyroxine
• Irritable bowel syndrome and medicinal mushrooms
• Reishi for sleep — what was measured and what was not
• Reishi and the immune system: modulation or boost?
• Drug interactions
• Do medicinal mushrooms have side effects?
• Fresh or dried mushroom
• Beta-glucan vs. polysaccharides
• Lab results — beta-glucan
• How to read a certificate of analysis (COA)
• Mushroom supplement regulation in Israel
• Medicinal mushrooms by goal — the hub

This page is educational and does not constitute medical advice, diagnosis or a substitute for professional care. Medicinal mushroom extracts are dietary supplements, not drugs, and are not intended to treat celiac disease or any other medical condition. Our extracts have not been tested for the presence of gluten. Celiac disease requires medical diagnosis and medical and nutritional follow-up; do not start or stop a gluten-free diet before diagnostic testing, and do not change the dose of levothyroxine or any other medication without your physician’s guidance. It describes what published trials and case reports recorded — and what was not recorded; it is not a prediction of what any individual will experience, and it is not a recommendation to start, stop or combine any supplement with any medication — those decisions belong with your physician, especially if you take regular medication, are pregnant or breastfeeding, have liver or kidney disease, avoid alcohol, or have any existing medical condition. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.