Hashimoto’s and Natural Treatment: What Was Measured, and What About Levothyroxine

Hashimoto’s (chronic autoimmune thyroiditis) is the common cause of an underactive thyroid, and “natural treatment” follows it in search — alongside medicinal mushrooms such as reishi (Ganoderma lucidum, lingzhi) and cordyceps. The honest answer: none of our four fruiting-body mushrooms has been tested in people with Hashimoto’s or alongside levothyroxine (Synthroid). What was tested, in two Chinese studies with no placebo, is a fermented cordyceps-mycelium drug. Levothyroxine absorption is sensitive to whatever is swallowed around it, so the question is timing, and what to tell your doctor.

The kinds of evidence that do exist, from closest to a person to furthest away: on the drug — absorption reviews of levothyroxine, a trial of 8 volunteers with fiber, a survey of 925 patients, and one case report in which an off-the-shelf supplement moved TSH; on the symptom — a survey of 397 patients with normal TSH who still have complaints, and a reishi fatigue trial in a different population; on the disease — two human studies and two in rodents, all with mycelium preparations or a fungus related to cordyceps, and zero in thyroiditis on reishi, lion’s mane or turkey tail; and on what we do not sell — a Cochrane review and meta-analyses on selenium and on a gluten-free diet. This page is written around what you are asking, and says of every item what it is — and what it is not. The wider picture across all autoimmune diseases is on the medicinal mushrooms and autoimmune disease page.

Is there a natural treatment for Hashimoto’s — and what do medicinal mushrooms do to the thyroid?

For the four fruiting-body mushrooms we grow — not measured in humans. What was measured in Hashimoto’s and Graves’ patients is a Chinese drug made from fermented cordyceps mycelium, in two studies with no placebo; and in rodents — two studies. Reishi, lion’s mane and turkey tail have not been tested in autoimmune thyroiditis or hypothyroidism — not in humans and not in animals. The treatment for Hashimoto’s is replacement hormone — levothyroxine — and no supplement has been tested as a substitute for it.

To understand what the question really is, you need to know what the disease does. In Hashimoto’s the immune system attacks the thyroid gland, and the gland gradually loses its ability to make hormone. A 2022 review in Nature Reviews describes chronic autoimmune thyroiditis as the common cause of hypothyroidism in iodine-sufficient regions, and levothyroxine as one of the most prescribed drugs in the world. In other words, the disease itself shows up as a hormone deficit, and the treatment makes up the deficit. A supplement that “helped Hashimoto’s” would have to prove one of two things: that it slows the destruction of the gland (measured by TPOAb antibodies and by a fall in TSH over time), or that it eases symptoms that persist even when the hormone is balanced. For our four fruiting-body mushrooms, neither has been measured in humans; for a fermented cordyceps-mycelium drug, the first — antibodies — was measured, in two studies with no placebo, and we detail them in a chapter of their own.

And so this page is built differently. It does not ask “which mushroom for Hashimoto’s” — it asks what you actually ask: can you take a supplement alongside levothyroxine, how long to separate them, why the fatigue stays when TSH is normal, what is true about the claim that “reishi balances the thyroid”, what was actually tested in humans on cordyceps, and what was measured on things we do not sell — selenium and a gluten-free diet. And if your gland is actually overactive — there is a chapter on Graves’.

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

The table sorts the questions you ask by what was measured on them and in which organism. The rows for our four mushrooms are empty or in rodents; the only human row on a mushroom is a Chinese mycelium drug, with no placebo. The levothyroxine rows hold human evidence on fiber and supplements — not on mushrooms. And the only rows with trials in Hashimoto’s patients themselves are selenium and a gluten-free diet, which we do not sell.

Can you take medicinal mushrooms with levothyroxine (Synthroid)?

On our four mushrooms — not tested, for better or for worse; a Chinese cordyceps-mycelium drug was given alongside levothyroxine in two studies, but the drug’s absorption was not measured in them. What is known: levothyroxine is a drug with a narrow therapeutic window, its absorption is sensitive to everything swallowed around it, and an innocent off-the-shelf supplement has already moved a stable TSH in one patient. The wording you can stand behind: “not measured in humans — a question for the pharmacist, with separation in time”.

What the market claims. Two opposite claims, both without measurement: “mushrooms are natural, so there is no problem combining them” — and “mushrooms stimulate the immune system, so they are forbidden in Hashimoto’s”. The first ignores how the drug is absorbed; the second confuses the drug with the disease — levothyroxine is not an immunosuppressant, it is a replacement hormone. The immune question gets its own chapter below.

What exactly was measured — on the drug. A 2017 review in Clinical Therapeutics states that levothyroxine is given in micrograms and has a narrow therapeutic index, so interactions at the absorption stage are clinically significant; the main mechanism is adsorption — the drug binds to the interfering substance in the gut, and less of it is available for absorption. The same review writes that the effect of dietary fiber “is still not fully understood”. A 2021 systematic review screened 121 studies and included 63, and found “limited” evidence of interaction with coffee, soy, fiber, calcium or iron — “but all of them resulted in reduced absorption”. And a 2025 review explains that the drug is absorbed in the small intestine within about three hours, that it depends on stomach acidity, and recommends separating it by 3–4 hours from any interfering food or drug; the authors of that review work for a pharmaceutical company, so it does not stand here on its own.

And the other side — which has to be written, and has two sides of its own. In 1996, doctors at Soroka in Beer Sheva described hypothyroid patients who needed unusually high levothyroxine doses and were taking a dietary fiber supplement: when the fiber was stopped, at a constant dose, TSH fell — or the dose required fell; and in vitro, wheat bran adsorbed levothyroxine in a dose-dependent way. This is a case series, and the number of patients does not appear in the abstract. A trial from 1998 went the other way: 8 volunteers took 600 mcg once alone, once with 1,000 mg of polycarbophil and once with 3.4 grams of psyllium — absorption was 89%, 86% and 80%, with overlapping confidence intervals, and the authors concluded that no malabsorption detectable by this method is expected. Eight people is a tiny sample: this is an absence of proof at low statistical power, not proof that there is no problem — and against the Soroka cases, the evidence on fiber is not uniform.

A supplement that moved TSH — the documented case. In 2021, doctors in Sri Lanka described a 34-year-old woman with primary hypothyroidism whose TSH had been stable within the normal range for three years on 125 mcg. She added an off-the-shelf whey protein supplement, her TSH rose and her symptoms returned in mild form. Good adherence, the same brand, no pregnancy, no other drugs or herbs. She stopped the supplement alone — and 6 weeks later her TSH was 1.7. This is one case, and it is not about mushrooms. But it is the proof that the question “a supplement alongside levothyroxine” is not theoretical. And it is not a question for the few: in the CONTROL survey of 925 patients on levothyroxine, 51.8% took dietary supplements, 68.0% consumed food or drink rich in fiber, iodine or soy, and those with a gastrointestinal comorbidity were almost 2 times as likely to have frequent dose changes. The survey is questionnaire-based and was funded by a pharmaceutical company.

Why this does not automatically carry over to mushrooms. Beta-glucan is a soluble fiber, so the link to the fiber literature makes sense — but it is mechanistic only. Nobody has measured how much beta-glucan reaches the gut from a serving of liquid extract, and nobody has measured levothyroxine absorption after a mushroom; in the Chinese studies of cordyceps mycelium, hormones and antibodies were measured after 24 weeks — not the absorption of a dose. What can be known today: that every supplement — mushroom, protein, calcium or iron — is a variable in absorption, and that separation in time is the tool you have. What to ask your doctor or pharmacist: “I am starting a new supplement — how many hours should I separate it from my levothyroxine, and when should I check TSH again?” The wider list is on the drug interactions page.

How many hours should separate levothyroxine from a supplement — and what about coffee?

A 2025 review recommends 3–4 hours between levothyroxine and any food, drug or supplement that may interfere; the other reviews say “separate in time” without naming a number. Coffee and soy appear in the reviews as having the largest effect on absorption, alongside calcium and iron. Taking it in the morning on an empty stomach and taking it at bedtime were found equally effective. The time you take it, and the gap, are set with your doctor.

“Levothyroxine and coffee” and “when to take levothyroxine” are two of the first searches Google completes for the drug’s name in Israel — and rightly so. The 2017 review lists soy and coffee as having the largest effect in reducing absorption, and vitamin C, on the contrary, as an enhancer; it attributes the consistent and significant decrease to a series of drugs — calcium, ferrous sulfate, proton pump inhibitors and others — and says explicitly that all of these can be avoided by separating dosing times. The 2021 systematic review adds that morning and bedtime dosing are equally effective, and that keeping a gap between the drug and coffee, calcium or iron is the practical way to cancel the interaction. The 2025 review also highlights espresso coffee and grapefruit juice.

And what about a mushroom supplement? We have no number, so we are not inventing one. The cautious logic is to treat it like any other supplement: not in the same sip as the pill, and at the gap your doctor has set for supplements. And one thing worth telling the pharmacist: a liquid mushroom extract contains alcohol — in our extracts, 32% — and that is a data point relevant to any medication list. “Which levothyroxine brand” — another question Google completes — is your doctor’s decision; the brand names are all levothyroxine, and switching between products is another reason to check TSH.

Atrophic gastritis, H. pylori and celiac disease — why do they move the dose?

Because levothyroxine needs an acidic stomach and a healthy small intestine to be absorbed. H. pylori and atrophic gastritis raise stomach pH; celiac disease changes the absorptive surface of the small intestine. In a survey of 925 patients, 47.0% reported a comorbidity that can impair absorption — mainly reflux, irritable bowel, lactose intolerance and bowel surgery, not atrophic gastritis or celiac disease. If your dose keeps climbing without explanation — that is the question for the endocrinologist, before any supplement.

This is where “natural treatment” meets medicine in the most practical way. The 2017 review lists celiac disease, atrophic gastritis, lactose intolerance and H. pylori infection as conditions that can impair levothyroxine absorption, and warns that while they are being treated, TSH and free T4 need to be monitored — because when absorption improves, the same dose may become too high. A 2018 review in the European Journal of Endocrinology lists among the reasons many patients “remain hypothyroid” despite treatment: malabsorption syndromes, autoimmune gastritis, drugs, and a “high-fiber diet” — and the most common reason of all is simply not taking the drug regularly. And in the CONTROL survey, 47.0% of patients reported at least one comorbidity that can impair absorption — reflux (33.8% on its own), irritable bowel, lactose intolerance or bowel surgery; atrophic gastritis, H. pylori and celiac disease are not on that list.

Celiac disease and Hashimoto’s. A 2026 review writes that celiac disease and Hashimoto’s “frequently occur together”, and a Mendelian randomization study from the same year found that the genetic predisposition to Hashimoto’s raises the risk of celiac disease (OR 1.544). The review recommends targeted screening for celiac disease in some Hashimoto’s patients — not removing gluten for everyone. On the other side of this crossroads — what is in the supplement, what the mushroom grows on, and whether it contains grain — we wrote on the celiac disease and supplements page.

Why does the fatigue stay even when TSH is normal — and what was measured on it?

It is a real, measured complaint: in a community survey of 397 patients on thyroxine with normal TSH, 48.6% reported symptoms on a thyroid questionnaire versus 35.0% of controls. On mushrooms for Hashimoto’s fatigue — zero studies. The cleanest reishi trial in fatigue was done in neurasthenia: a 28.3% drop versus 20.1% on placebo. Not Hashimoto’s, and the difference is smaller than it looks.

What was measured on the complaint itself. In 2002, British researchers sent a questionnaire to 961 patients on thyroxine and to age- and sex-matched controls; 597 patients and 551 controls replied. Among 397 patients whose latest TSH was normal, 34.4% crossed the distress threshold on the General Health Questionnaire versus 25.6% of controls, and 48.6% versus 35.0% on the thyroid symptom questionnaire. The differences remained significant after adjusting for age, sex, illness and medication — and the authors themselves write that they are “not large”. The 2022 Nature Reviews review confirms: after TSH and T4 are normalized, “a substantial proportion” of patients continue to have complaints that impair their quality of life. In other words, if you are tired with normal tests — you are not imagining it.

What was measured on reishi in fatigue. The largest and cleanest trial, from 2005: 132 neurasthenia patients in China, reishi polysaccharide 1,800 mg three times a day, 8 weeks, double-blind. The feeling of fatigue fell by 28.3% — and on placebo by 20.1%. The real difference is about eight percentage points, not 28. In the clinical assessment, 51.6% of the reishi group were rated “more than minimally improved” versus 24.6% on placebo (p=.002). Neurasthenia is not Hashimoto’s, and nobody has tested this in people who are tired on levothyroxine. Another trial, in 64 women with fibromyalgia, found improved physical fitness — but the comparison group received carob, not placebo; we detailed it on the fibromyalgia page. And cordyceps, sold as “the energy mushroom” — small fitness trials in humans gave mixed results, and on fatigue there is no trial.

What can be known today. Fatigue with normal TSH is a question for the endocrinologist, and it is an open one in medicine itself. Before looking for a mushroom for it, it is worth ruling out what is known to shift the balance — absorption, dose, comorbidities — and remembering that the next chapter shows that reishi, at a high dose and in a different fatigued population, came with higher symptom severity than placebo.

What happened when reishi was tested in a population with chronic fatigue?

At the high dose, symptom severity was higher than on placebo (p=0.012); at the low dose — no change (p=0.603). This was measured in 2021, in a placebo-controlled, pseudo-randomized crossover trial in 29 men with Gulf War illness. This is not Hashimoto’s and not an “autoimmune flare” — but it is the second fatigued population in which reishi was measured against placebo on symptoms, and there the direction was reversed.

Gulf War illness is a multi-system condition of chronic fatigue, pain and a neuro-inflammatory component that affects soldiers who served in the Gulf War. It has no direct connection to the thyroid. We bring it because it maps exactly onto the complaint in the previous chapter — fatigue with no explanation in the lab — and because it is one of the few times reishi was tested in humans with persistent fatigue in a controlled trial. The design: 30 days of baseline, 30 days of placebo, 30 days of low dose and 30 days of high dose. The authors’ conclusion, word for word: “reishi may exaggerate symptoms in some GWI sufferers”. And in the same breath: “the results come from a small sample and are preliminary”.

What this tells you, and what it does not. It does not say that reishi worsens Hashimoto’s — that was not tested. It says that the sentence “medicinal mushrooms can’t hurt; at worst they won’t help” does not stand up to the data: in one of the two controlled trials that measured symptoms in a fatigued population, the direction was reversed and dose-dependent. If you start a supplement — any supplement — and feel worse, that is a data point you measure on yourself. You stop, and you tell your doctor.

“Reishi balances the thyroid” — what is that based on?

On no reishi study in humans, and on no reishi study in an animal with thyroiditis. What exists is on cordyceps, not reishi: two rodent studies — a fungus isolated from cordyceps in mice with iodine-induced thyroiditis, and a mycelium preparation in rats — and two human studies of a mycelium drug, in the next chapter. “Balances” is a marketing word; what was measured with purified beta-glucan from reishi in humans is a rise in immune markers, not balance.

What the market claims. “Reishi regulates the immune system and therefore balances the thyroid”, “reishi for an underactive and an overactive thyroid alike”. Google completes “reishi mushroom thyroid gland” — the demand is there, and the answers online are written without a source.

What exactly was measured. Two studies, both in rodents, and neither of them reishi. In 2021, a fungus called Isaria felina — isolated from cordyceps and not cordyceps itself — was given at 300 or 600 mg per kg a day, for 4 weeks, to mice in which thyroiditis had been induced with iodine. Only the high dose lowered TSH, thyroid antibodies and cytokines; the low dose did nothing significant. In 2024, the Bailing capsule, a cordyceps mycelium preparation, was given to rats with autoimmune thyroiditis: T3, T4 and TPO and TG antibodies fell, and inflammatory cytokines fell. The dose and the number of rats do not appear in the abstract.

Why this does not automatically carry over to humans. Iodine-induced thyroiditis in a mouse is a model of days and weeks; Hashimoto’s in humans develops over years. 600 mg per kg in a mouse is not a dose anyone takes. And the preparations tested — a different fungus and a mycelium — are not a fruiting-body extract. What can be known today: that the claim about reishi specifically has no measured basis at any level, and that the claim about cordyceps rests on rodents and on two Chinese studies of a fermented-mycelium drug, with no placebo — not on fruiting body. What to ask your doctor: not “does reishi balance” — but “has anything been tested on TPO antibodies in humans”, and the answer is in the next chapter and in the chapter on selenium.

Has cordyceps been tested in people with Hashimoto’s or Graves’ — and what exactly was tested there?

Yes — but not the mushroom in the bottle. Two Chinese studies tested a drug made from fermented cordyceps mycelium on top of the usual drug: a 2016 randomized trial in 56 Hashimoto’s and 44 Graves’ patients, with no placebo, and a 2024 retrospective analysis of 70 patients. In both, TPO antibodies were lower in the drug group. On cordyceps fruiting body — like ours — zero.

What the market claims. “Cordyceps for the thyroid”, “cordyceps lowers antibodies” — and sometimes a citation of “a Chinese clinical study” without saying what was tested in it. These studies do not come up in a search for “mushroom”, because the preparations are registered in China as drugs under trade names — Corbrin, Bailing, Jinshuibao — which makes them easy both to miss and to wave around.

What exactly was measured. In 2016, at one university hospital in China, 56 Hashimoto’s patients and 44 Graves’ patients were randomly assigned to an intervention or a control group. The controls received levothyroxine (in Hashimoto’s) or methimazole (in Graves’) alone; the intervention groups received the same drug plus Corbrin capsules — a preparation made from cordyceps mycelium by fermentation — 2 grams three times a day for 24 weeks. Thyroid hormones, antibodies and T-cell subsets were measured. TPO antibodies fell significantly in both intervention groups, and the helper/cytotoxic T-cell ratio moved in opposite directions in the two diseases. There was no placebo group, blinding — whether patients knew what they were taking — is not described in the abstract, and funding does not appear in it. In 2024, at a city hospital in China, the records of 70 autoimmune thyroiditis patients were analyzed retrospectively: 35 on levothyroxine alone, 35 on levothyroxine plus Bailing capsules — also fermented cordyceps mycelium. In the drug group the “total effective rate” was 94.29% versus 77.14%, free T4 20.05 versus 13.00 pmol/L, TPO antibodies 298.7 versus 735.2 U/mL, and inflammatory markers were lower; adverse reactions — no difference. The definition of “effective” does not appear in the abstract, and nobody assigned the patients at random. And in Graves’, a 2024 network meta-analysis gathered 35 Chinese randomized trials in 2,828 patients of traditional Chinese medicine preparations alongside antithyroid drugs, among them Bailing and Jinshuibao — both fermented cordyceps mycelium; the trials came mostly from Chinese databases, and the conclusion is only as good as the original trials.

Why this does not automatically carry over to our bottle. First, the material: Corbrin and Bailing are mycelium grown by fermentation in a tank and registered in China as drugs — not fruiting body, not a liquid extract, and not what we grow; composition and dose are not comparable. Second, the design: no placebo and no description of blinding, and in the 2024 study no random assignment either — the two things that make it hard to know how much of the effect belongs to the preparation. Third, the endpoint: a fall in TPO antibodies is the same marker selenium moved — and there, as written below, Cochrane found the clinical meaning unclear; quality of life, fatigue and levothyroxine dose over time were not reported in the abstracts. Fourth, each study comes from a single Chinese hospital, and we found no replication outside China.

What can be known today. That the sentence “no mushroom preparation has been tested in humans with Hashimoto’s” is not true: a cordyceps-mycelium preparation was tested, TPO antibodies were measured, and they fell. And that the sentence “cordyceps lowers antibodies” rests on two studies with no placebo of a Chinese drug — not on a fruiting-body extract, and not on a single participant outside China. What to ask your doctor: “There are studies on Corbrin and Bailing in Hashimoto’s — do they say anything about an over-the-counter cordyceps supplement?” An endocrinologist’s honest answer will probably be: not the same material, not the same design — and in any case, not instead of levothyroxine.

Mushrooms stimulate the immune system — is that a problem in an autoimmune disease?

Unknown, and that is the honest question. In healthy people, beta-glucan from reishi raised CD3, CD4, CD8 and NK cells versus placebo over 84 days; in cancer patients, a Cochrane meta-analysis found a 3.91% rise in CD3. That is measurable stimulation. What beta-glucan from reishi — or any fruiting body — does to antibodies against the thyroid, nobody has measured; in humans, TPO antibodies were measured only after a Chinese cordyceps-mycelium drug, with no placebo. A report of a flare — there is none.

The question is legitimate, and it must not be turned into either an alarm or a reassurance. On one side, in 2023 researchers in Taiwan gave beta-1,3;1,6-glucan from reishi to healthy adults aged 18–55 for 84 days, double-blind, and found a significant rise in CD3, CD4, CD8, the CD4/CD8 ratio and NK cells, and a difference in IgA — with no change in kidney or liver function. 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 that was “not adequate”. That is the direction measured: a rise — not two-way “balance”. We expanded on this on the reishi and the immune system page.

On the other side, in the search we ran, not a single case report was found of an autoimmune disease flaring after reishi, lion’s mane, cordyceps or turkey tail. And that does not prove safety: the adverse-event reporting system for supplements is partial and far looser than the one for drugs, and a doctor whose patient got worse usually will not suspect the supplement. In Hashimoto’s the question has a particular shape: the drug itself is not an immunosuppressant, so there is no “clash” here between drug and supplement — the question is about the disease. The marker measured in it is TPO antibodies; in humans they were measured after a cordyceps-mycelium drug — and fell, in two studies with no placebo — and were not measured after any of our four fruiting-body mushrooms, nor after reishi in any form. “Not tested” is neither “safe” nor “dangerous”. It is a data void, and anyone who writes otherwise in either direction — is making it up.

Reishi for sleep with Hashimoto’s — is there research on it?

No. There is not a single randomized trial in humans on reishi and sleep — not in Hashimoto’s and not at all. A dedicated PubMed search returned one result, and it is a study of fitness in fibromyalgia. That is surprising, because “reishi for sleep” is the most common search about reishi in Israel. Poor sleep with Hashimoto’s is a matter for the doctor, not for a mushroom.

What the market claims. Six of Google’s fifteen completions for “reishi for…” are about sleep: “reishi for sleep”, “before bed”, “reishi drops for sleep”. The whole market sells reishi for sleep. What exactly was measured. In the 2005 fatigue trial, fatigue and sense of well-being were measured — not sleep. For lion’s mane, a 2010 trial of 30 women explicitly measured the Pittsburgh Sleep Quality Index, and did not report it as a significant result. What can be known: that in Hashimoto’s the dose itself also shifts — when absorption improves, the same dose may become too high, and that is measured with a TSH test, not with a supplement. Everything that was and was not tested on reishi and sleep is gathered on the reishi for sleep page.

And if the gland is actually overactive — Graves’, methimazole and PTU?

On our four mushrooms with methimazole or PTU — zero studies; a Chinese cordyceps-mycelium drug was added to methimazole in 44 Graves’ patients, with no placebo, and liver function was not reported in the abstract. What is known is about the drugs: both can injure the liver, PTU more severely, and since 2009 it has carried an FDA “black box” warning. So in Graves’ the supplement question is first of all a liver question — and reishi has case reports of liver injury. A question for the doctor, not a decision to make alone.

What was measured on the drugs. A 2014 review describes PTU as a cause of severe liver failure, mainly in children, and recounts that after reports over the years the FDA issued a “black box” warning in 2009, followed by the European and British authorities; methimazole and carbimazole are linked to less severe liver injury and are preferred. An analysis of more than 40 years of FDA adverse-event reports found over-reporting of severe liver injury with PTU under age 17 (adjusted reporting ratio 17), and with methimazole — mild, cholestatic injury from age 61 up. A 2020 review concludes that liver injury from antithyroid drugs is rare and idiosyncratic, and that hyperthyroidism itself also comes with abnormal liver function.

What is known about the mushrooms and the liver. A 2023 case report: a 47-year-old man developed acute hepatitis after reishi powder with alcohol, and recovered within two weeks. The NIH’s LiverTox database rates reishi as a “possible rare cause” of liver injury, and cordyceps and lion’s mane as “unlikely”. None of our four fruiting-body mushrooms has been tested alongside methimazole. This is exactly the place where “not tested” calls for double caution, and we detailed what is known on the medicinal mushrooms and the liver page.

The trap: “lion’s mane lowers palpitations”. In Graves’, anxiety and palpitations are the central complaint, and some online cite a 2010 trial for this: 30 women, lion’s mane cookies for 4 weeks, a study that also measured menopausal symptoms. Against placebo, only two items on the complaints questionnaire were significant — one of them “palpitatio”, palpitations. “Anxiety” and “concentration” only tended to fall. This is not a Graves’ population, heart rate was not measured in it, and it is one questionnaire item in 30 women. In Graves’, what lies behind the palpitations is measured with a blood test, at the doctor’s.

What was measured in Hashimoto’s that we do not sell — selenium and a gluten-free diet?

Both were tested in Hashimoto’s patients themselves: selenium moved TPO antibodies; a gluten-free diet moved TSH and free T4, not antibodies. Selenium: a 2013 Cochrane review found 4 trials in 463 participants and “incomplete” evidence; a 2024 meta-analysis of 35 studies found a fall in TPO antibodies, and in TSH among those not taking hormone. Gluten: 4 studies, 87 patients, antibodies did not fall significantly. We sell neither of them.

In Hebrew, “Hashimoto’s diet” and “Hashimoto’s naturopathy” are leading searches — which is why this chapter exists: these are the interventions that were actually tested, and it is worth knowing them before you buy something that was not. Selenium. The 2013 Cochrane review found 4 trials at unclear to high risk of bias, which could not be pooled (heterogeneity of 99%); quality of life and levothyroxine dose were not measured in any of them; selenomethionine 200 mcg lowered TPO antibodies in two trials, but “the clinical relevance is unclear”. A 2024 meta-analysis in Thyroid had already gathered 35 studies: in patients not taking hormone, TSH fell slightly (7 cohorts, 869 participants); TPO antibodies fell (29 cohorts, 2,358 participants, with heterogeneity of 90%); T4, T3 and gland volume did not change; and side effects were similar to control. Certainty: “moderate”.

A gluten-free diet. A 2023 meta-analysis of observational studies in Hashimoto’s patients without celiac disease: 4 studies, 87 patients, about half a year of avoiding gluten. TSH fell and free T4 rose significantly, but TPO and TG antibodies — did not (p=0.07 and p=0.06). The authors: the evidence is “still not sufficient” to recommend it to all Hashimoto’s patients. The 2026 Mendelian randomization study found no protective effect for gluten-free eating at the genetic level, and the review from the same year recommends targeted celiac screening instead of blanket restriction. We bring these numbers because they are what was measured — not to recommend; selenium dosing and diet changes belong with the endocrinologist and the dietitian.

What we actually measure in our bottle

After a whole page of “not measured”, you deserve to know what was measured — and about what exactly. We grow the mushrooms ourselves, on a farm in the Galilee: fresh fruiting body, not mycelium — like the preparations tested in rats and in Hashimoto’s patients in China — not mycelium grown on grain, and not imported powder whose name on the sack cannot be verified. 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 cordyceps 1:2.5. Alcohol in the finished extract: 32% — a figure worth bringing to the pharmacist together with the name of your drug.

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. Alpha-glucan not detected is the chemical proof that there is no grain in the bottle — a data point that matters especially to anyone who also has celiac disease. 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; and fresh fruiting body from the farm, which is what we do. And on a page that talks about absorption, it should also be said: we have not measured what a serving of the extract does to levothyroxine absorption, and nobody has — so we will not write “does not interfere”. 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. Kosher certification — Mateh Yehuda Rabbinate, Rabbi Gad Atias. That is what we know how to measure and prove about what is in the bottle. What it will do for Hashimoto’s or the thyroid 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 reishi, lion’s mane, cordyceps or turkey tail balance the thyroid, lower antibodies, slow Hashimoto’s or replace levothyroxine — at any dose and in any form; none of them, as fruiting body, has been measured in humans with Hashimoto’s — what was measured is a Chinese cordyceps-mycelium drug, in two studies with no placebo, and we do not claim that this says anything about our extract. We do not claim that mushrooms impair levothyroxine absorption — that was not measured; and we do not claim that they do not impair it — that was not measured either. We do not claim they are dangerous in an autoimmune disease, nor that they are safe in one. We do not claim that reishi eases fatigue or improves sleep in Hashimoto’s — the fatigue trial was done in a different population, and on sleep there is no trial at all. We do not claim that selenium or a gluten-free diet are “proven” — selenium moved antibodies, a gluten-free diet moved TSH, and the clinical meaning is unclear; and we do not sell them. And we do not deal here with disability benefits, disability ratings, pregnancy or T3 preparations — we have no expertise in those and no sources on them. What we do say: Hashimoto’s is diagnosed and monitored by a physician or endocrinologist; anyone taking levothyroxine, methimazole or PTU — talks to the doctor or pharmacist before any supplement, including ours. Under DSHEA, a dietary supplement may not claim to diagnose, treat, cure or prevent any disease. We sell mushroom extracts, and we are telling you explicitly not to buy them for your thyroid.

The bottom line

Our four fruiting-body mushrooms have not been tested in humans with Hashimoto’s or Graves’; what exists is two Chinese studies of a drug made from fermented cordyceps mycelium — added to the drug, no placebo, one of them retrospective — in which TPO antibodies fell, and two rodent studies; on reishi — zero, in any organism with thyroiditis. The claim that “reishi balances the thyroid” rests on no measurement, and what was measured with purified beta-glucan from reishi is a rise in immune markers. The practical question is absorption: levothyroxine is sensitive to everything swallowed around it, a review of 63 studies found limited evidence for coffee, soy, fiber, calcium and iron — all in the direction of reduced absorption — and one off-the-shelf supplement has already moved a stable TSH; so every supplement gets a gap in time (a 2025 review names 3–4 hours) and a TSH test, coordinated with your doctor. The fatigue with normal TSH is real and measured, and there is no research on mushrooms for it; and in a different fatigued population, high-dose reishi came with higher symptom severity than placebo. And if someone sells you a mushroom “for the thyroid” — send them this page, and go to an endocrinologist.

Frequently asked questions

Is there a natural treatment for Hashimoto’s?

The treatment for Hashimoto’s is replacement hormone — levothyroxine — and no supplement has been tested as a substitute for it. What was tested in Hashimoto’s patients themselves: selenium moved TPO antibodies, a gluten-free diet moved TSH — and the clinical meaning is unclear. Of our four mushrooms, as fruiting body, none has been tested in humans with Hashimoto’s; a Chinese drug made from cordyceps mycelium was tested in two studies with no placebo.

Can I take reishi with levothyroxine?

Not tested — no study has measured levothyroxine absorption after reishi or after any of our four mushrooms. It is known that the drug’s absorption is sensitive to what is swallowed around it, and that a review of 63 studies found limited evidence for coffee, soy, fiber, calcium and iron — all in the direction of reduced absorption. It is a question for the pharmacist: at what gap to take it, and when to check TSH again after starting a new supplement.

How long should I wait between levothyroxine and coffee or a supplement?

A 2025 review recommends 3–4 hours between levothyroxine and any food, drug or supplement that may interfere; the other reviews say “separate in time” without a number. Coffee and soy appear as having the largest effect, alongside calcium and iron. Taking it in the morning on an empty stomach and taking it at bedtime were found equally effective. The exact time and gap are set with your doctor.

Does reishi balance the thyroid?

On reishi there is not a single study on it — neither in humans nor in an animal with thyroiditis. What exists is on cordyceps: two rodent studies, and two Chinese human studies of a drug made from fermented mycelium, with no placebo — not reishi and not fruiting body. And what was measured with purified beta-glucan from reishi in humans is a rise in immune markers, meaning stimulation, not “balance”.

Why am I tired even when my TSH is normal?

It is a known, measured complaint: in a survey of 397 patients on thyroxine with normal TSH, 48.6% reported symptoms on a thyroid questionnaire versus 35.0% of controls, and a 2022 review writes that a substantial proportion of patients continue to have complaints. It is a question for the endocrinologist — absorption, dose and comorbidities come before any supplement.

Does selenium help Hashimoto’s?

A 2013 Cochrane review found 4 trials in 463 participants and “incomplete” evidence. A 2024 meta-analysis of 35 studies found a fall in TPO antibodies, and a small fall in TSH among those not taking hormone; T4 and gland volume did not change. We do not sell selenium, and the dose is set by the endocrinologist.

A gluten-free diet in Hashimoto’s — is there a basis for it?

A 2023 meta-analysis of 4 studies in 87 patients without celiac disease found that TSH fell slightly, but TPO and TG antibodies did not fall significantly; the authors wrote that the evidence is not sufficient to recommend it to everyone. A 2026 review recommends celiac screening in some Hashimoto’s patients instead of blanket restriction.

I have Graves’ and I am on methimazole — what about mushrooms?

On our four mushrooms — zero studies with methimazole or PTU; a Chinese cordyceps-mycelium drug was given alongside methimazole in 44 Graves’ patients, with no placebo. Both drugs can injure the liver, PTU more severely and with an FDA warning from 2009, and reishi has case reports of liver injury. So in Graves’ the question is first of all a liver question — and it belongs with the doctor, with liver function tests.

Scientific sources (peer-reviewed)

• Levothyroxine — narrow therapeutic index, given in micrograms; interactions at the absorption stage are clinically significant; mechanism: adsorption; the effect of fiber “is still not fully understood”; celiac disease, atrophic gastritis and H. pylori impair absorption; solution: separating dosing times — Skelin M, et al. Clinical Therapeutics, 2017. View on PubMed
• Systematic review, 63 studies: “limited” evidence of interaction with coffee, soy, fiber, calcium and iron — “but all of them resulted in reduced absorption”; morning and bedtime dosing equally effective — Wiesner A, et al. Pharmaceuticals (Basel), 2021. View on PubMed
• Absorption within about three hours, dependent on stomach acidity; fiber, espresso and grapefruit interfere — separate by 3–4 hours; H. pylori and atrophic gastritis raise pH, celiac disease changes the absorptive surface. Authors from a pharmaceutical company — Mana DL, Rizzo LFL. Medicina (B Aires), 2025. View on PubMed
• Pitfalls in replacement therapy: many patients remain hypothyroid because of malabsorption, autoimmune gastritis, drugs, a “high-fiber diet” — and above all non-adherence — de Carvalho GA, et al. European Journal of Endocrinology, 2018. View on PubMed
• 8 volunteers, 600 mcg: absorption 89% alone, 86% with polycarbophil 1,000 mg, 80% with psyllium 3.4 grams — overlapping confidence intervals; no malabsorption detectable by this method is expected — Chiu AC, Sherman SI. Thyroid, 1998. View on PubMed
• Soroka, Beer Sheva: hypothyroid patients who needed unusually high levothyroxine doses and took a fiber supplement — stopping the fiber, at a constant dose, lowered TSH or the dose required; in vitro, wheat bran adsorbed levothyroxine dose-dependently. Case series, number of patients not in the abstract — Liel Y, et al. Journal of Clinical Endocrinology & Metabolism, 1996. View on PubMed
• Case report: a 34-year-old woman, TSH stable for 3 years on 125 mcg; an off-the-shelf protein supplement pushed TSH up; stopping it alone — TSH 1.7 after 6 weeks — Kumarathunga PADM, et al. Endocrinology, Diabetes & Metabolism Case Reports, 2021. View on PubMed
• CONTROL survey, 925 patients on levothyroxine: 51.8% take supplements; 68.0% consume food rich in fiber, iodine or soy; 47.0% with a comorbidity that can impair absorption; gastrointestinal disease — almost 2 times the odds of dose changes. Questionnaire survey, industry funding — McMillan M, et al. Drugs in R&D, 2016. View on PubMed
• 961 patients on thyroxine versus controls: among 397 with normal TSH — 34.4% versus 25.6% on the distress questionnaire and 48.6% versus 35.0% on the thyroid symptom questionnaire; the differences “are not large” but significant — Saravanan P, et al. Clinical Endocrinology, 2002. View on PubMed
• Hypothyroidism — review: chronic autoimmune thyroiditis is the common cause; after TSH and T4 are normalized, “a substantial proportion” of patients continue to have complaints — Chaker L, et al. Nature Reviews Disease Primers, 2022. View on PubMed
• 132 neurasthenia patients, reishi polysaccharide 1,800 mg ×3 a day, 8 weeks: fatigue −28.3% versus −20.1% on placebo; “more than minimally improved” 51.6% versus 24.6% (p=.002). Not Hashimoto’s — Tang W, et al. Journal of Medicinal Food, 2005. View on PubMed
• 64 women with fibromyalgia, reishi 6 grams a day for 6 weeks: improved fitness — versus carob, not versus placebo — Collado Mateo D, et al. Nutrición Hospitalaria, 2015. View on PubMed
• 29 men with Gulf War illness, placebo-controlled crossover: 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
• Beta-glucan from reishi, healthy adults aged 18–55, 84 days, double-blind: rise in CD3, CD4, CD8, the CD4/CD8 ratio and NK cells; difference in IgA; kidney and liver function unchanged — 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”; minor side effects — Jin X, et al. Cochrane Database of Systematic Reviews, 2016. View on PubMed
• Cochrane, reishi for 4 months: risk ratio 1.67 for an adverse effect — not significant, none serious — Klupp NL, et al. Cochrane Database of Systematic Reviews, 2015. View on PubMed
• The only randomized trial of one of our mushrooms in an autoimmune disease: 65 rheumatoid arthritis patients, reishi + San Miao San, 24 weeks — ACR20 15% versus 9.1%, not significant; zero change in immune cells — Li EK, et al. Arthritis and Rheumatism, 2007. View on PubMed
• A fungus isolated from cordyceps (Isaria felina), 300 or 600 mg per kg a day, 4 weeks, in mice with iodine-induced thyroiditis: only the high dose lowered TSH, antibodies and cytokines. Rodents only — Yang X, et al. Biomedicine & Pharmacotherapy, 2021. View on PubMed
• Bailing capsule (cordyceps mycelium) in rats with autoimmune thyroiditis: T3, T4, TPO and TG antibodies fell; dose and number of animals not in the abstract — Qixin W, et al. Journal of Traditional Chinese Medicine, 2024. View on PubMed
• Corbrin capsule — a Chinese drug made from fermented cordyceps mycelium — 2 grams ×3 a day, 24 weeks, added to levothyroxine in 56 Hashimoto’s patients and to methimazole in 44 Graves’ patients; random assignment, no placebo, blinding not described: TPO antibodies fell significantly in both intervention groups; the helper/cytotoxic T-cell ratio moved in opposite directions in the two diseases. Funding not in the abstract. Not fruiting body — He T, et al. Evidence-Based Complementary and Alternative Medicine, 2016. View on PubMed
• Bailing capsule (fermented cordyceps mycelium) + levothyroxine versus levothyroxine alone, 70 autoimmune thyroiditis patients (35 versus 35), retrospective analysis: “total effective rate” 94.29% versus 77.14%; free T4 20.05 versus 13.00 pmol/L; TPO antibodies 298.7 versus 735.2 U/mL; IL-6 and IL-17 lower; adverse reactions — no difference. Not randomized, not fruiting body — Su BY, et al. Medicine (Baltimore), 2024. View on PubMed
• Network meta-analysis in Graves’: 35 randomized trials, 2,828 patients, traditional Chinese medicine preparations — among them Bailing and Jinshuibao (cordyceps mycelium) — alongside antithyroid drugs; the search included Chinese databases (CNKI, WanFang, Weipu); the conclusion is only as good as the original trials — Yang Z, et al. Frontiers in Pharmacology, 2024. View on PubMed
• PTU, methimazole and carbimazole — hepatotoxicity: PTU causes severe liver failure, mainly in children; FDA warning in 2009; methimazole and carbimazole — less severe injury, preferred — Akmal A, Kung J. Expert Opinion on Drug Safety, 2014. View on PubMed
• More than 40 years of FDA reports: severe liver injury with PTU under age 17 (adjusted reporting ratio 17); with methimazole — mild cholestasis from age 61 — Rivkees SA, Szarfman A. Journal of Clinical Endocrinology & Metabolism, 2010. View on PubMed
• Thyroid and liver: liver injury from antithyroid drugs is rare and idiosyncratic; damage from PTU is usually more severe than from methimazole — Piantanida E, et al. Journal of Endocrinological Investigation, 2020. View on PubMed
• Case report: a 47-year-old man, acute hepatitis after reishi powder with alcohol, full recovery within two weeks — Guedikian R, et al. Cureus, 2023. View on PubMed
• 30 women, lion’s mane cookies for 4 weeks: against placebo only two questionnaire items significant — one of them “palpitatio”; sleep quality was measured and not reported as significant. Not Graves’ — Nagano M, et al. Biomedical Research (Tokyo), 2010. View on PubMed
• Gluten-free diet in Hashimoto’s without celiac disease — meta-analysis of 4 studies, 87 patients, about half a year: TSH fell, T4 rose; TPO and TG antibodies — not significant; “not enough evidence to recommend it to everyone” — Piticchio T, et al. Frontiers in Endocrinology, 2023. View on PubMed
• Mendelian randomization: Hashimoto’s raises the risk of celiac disease (OR 1.544); a gluten-free diet has no protective effect on autoimmune thyroid disease — Pu YH, et al. British Journal of Nutrition, 2026. View on PubMed
• Celiac disease and Hashimoto’s “frequently occur together”; not enough evidence for routine gluten removal in Hashimoto’s without celiac disease; targeted screening recommended — Fan X, et al. Frontiers in Endocrinology, 2026. View on PubMed
• Cochrane, selenium in Hashimoto’s: 4 trials, 463 participants, unclear to high risk of bias; quality of life and levothyroxine dose not measured; the evidence is “incomplete” — van Zuuren EJ, et al. Cochrane Database of Systematic Reviews, 2013. View on PubMed
• Selenium — meta-analysis of 35 studies: TSH fell in untreated patients (869 participants), TPO antibodies fell (2,358); T4 and gland volume unchanged; moderate certainty — Huwiler VV, et al. Thyroid, 2024. View on PubMed

Read next

• Medicinal mushrooms and autoimmune disease — the full picture
• Celiac disease and supplements — is there gluten in the extract?
• Medicinal mushrooms and the liver
• Fibromyalgia and supplements
• Reishi for sleep — what was measured and what was not
• Reishi and the immune system: regulation or boost?
• How mushrooms regulate the immune system
• Drug interactions
• Do medicinal mushrooms have side effects?
• Who shouldn’t take reishi
• Who shouldn’t take cordyceps
• Medicinal mushrooms by goal — the hub
• Lab results — beta-glucan
• How to read a certificate of analysis (COA)

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 Hashimoto’s, Graves’, hypothyroidism, hyperthyroidism or any other medical condition. Thyroid disease requires medical diagnosis and follow-up, including periodic TSH tests. Do not stop, replace or change the dose of levothyroxine, methimazole, PTU 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 surgery planned, or have liver or kidney disease or 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.*