Drug & supplement interaction

Shiitake Mushroom + Levothyroxine

Levothyroxine brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, and others.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 13, 2026

The bottom line No known interaction

We found no known interaction between Shiitake Mushroom and Levothyroxine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Levothyroxine states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Shiitake Mushroom and Levothyroxine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Levothyroxine and Shiitake Mushroom in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Shiitake Mushroom safety at a glance

Shiitake Mushroom overall Use caution Generally safe as a food, but concentrated supplements and raw mushrooms can cause reactions in some people.

Pregnancy Use caution Eating shiitake as food is likely fine, but concentrated supplements should be avoided due to lack of safety data.

Breastfeeding Use caution Food amounts are likely fine, but there is not enough data on supplement doses, so caution is advised.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Levothyroxine and Shiitake Mushroom? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Levothyroxine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Levothyroxine is filed under 3 classifications — including thyroid hormone, oral drugs. Shiitake Mushroom has documented interactions with 2 drug classes — the most serious being cytochrome p450 2d6 (cyp2d6) substrates (moderate) and immunosuppressants (moderate) — and none of Levothyroxine’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Shiitake Mushroom Does Interact With Other Medications

Shiitake Mushroom has 312 moderate known drug interactions in our database — Levothyroxine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 312 No known interaction 2,518 (incl. Levothyroxine)

Taking anything else?

Check Another of Your Medications Against Shiitake Mushroom

Covers the 2,830 medications we’ve checked against Shiitake Mushroom. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Shiitake Mushroom and Levothyroxine May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 4 of them are worth acting on rather than waiting out — marked below.

Wheezing Worth acting on Additional detail
Shiitake Mushroom
“Allergic contact dermatitis can occur by contact with shiitake hyphae (filaments). It appears to be more common in growers or others that handle shiitake mushrooms extensively. Contact or inhalation also results in other symptoms of allergy, such as asthma, rhinitis, conjunctivitis, and pneumonia.”

Shiitake Mushroom · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).
6 sources cited

1153. Ueda A, Obama K, Aoyama K, et al. Allergic contact dermatitis in shiitake (Lentinus edodes (Berk) Sing) growers. Contact Dermatitis 1992;26:228-33.

74785. Curnow, P. and Tam, M. Contact dermatitis to Shiitake mushroom. Australas.J.Dermatol. 2003;44(2):155-157. PubMed

111913. Sudy E, Urbina F. Shiitake dermatitis: clinical forms of presentation. Int J Dermatol 2023. PubMed

94241. Boels D, Landreau A, Bruneau C, et al. Shiitake dermatitis recorded by French Poison Control Centers - new case series with clinical observations. Clin Toxicol (Phila). 2014 Jul;52(6):625-8. PubMed

94259. Ricar J, Pizinger K, Cetkovska P. Shiitake dermatitis: a distinctive clinical entity. Int J Dermatol. 2013 Dec;52(12):1620-1. PubMed

94249. Kopp T, Mastan P, Mothes N, Tzaneva S, Stingl G, Tanew A. Systemic allergic contact dermatitis due to consumption of raw shiitake mushroom. Clin Exp Dermatol. 2009 Dec;34(8):e910-3. PubMed
“In mushroom workers, hypersensitivity pneumonitis due to shiitake spore inhalation has occurred. Symptoms include difficulty breathing, chest pain, a dry cough, asthma, and rhinitis.”

Shiitake Mushroom · Natural Medicines adverse-effect record, reported in asthma.
6 sources cited

1150. Murakami M, Kawabe K, Hosoi Y, et al. Decreased pulmonary perfusion in hypersensitivity pneumonitis caused by Shiitake mushroom spores. J Intern Med 1997;241:85-8. PubMed

1151. Matsui S, Nakazawa T, Umegae Y, Mori M. Hypersensitivity pneumonitis induced by Shiitake mushroom spores. Intern Med 1992;31:1204-6.

74776. Fujiwara, K., Sato, T., Yonei, T., Genba, K., Nogami, N., and Yamadori, I. [A case of chronic hypersensitivity pneumonitis induced by shiitake mushroom spores]. Nihon Kokyuki.Gakkai Zasshi 2000;38(12):908-913.

74813. Sastre, J., Ibanez, M. D., Lopez, M., and Lehrer, S. B. Respiratory and immunological reactions among Shiitake (Lentinus edodes) mushroom workers. Clin.Exp.Allergy 1990;20(1):13-19.

94239. Ampere A, Delhaes L, Soots J, Bart F, Wallaert B. Hypersensitivity pneumonitis induced by Shiitake mushroom spores. Med Mycol. 2012 Aug;50(6):654-7. PubMed

94241. Boels D, Landreau A, Bruneau C, et al. Shiitake dermatitis recorded by French Poison Control Centers - new case series with clinical observations. Clin Toxicol (Phila). 2014 Jul;52(6):625-8. PubMed
Levothyroxine

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›
Chest pain / Shortness of breath Worth acting on Additional detail

Shiitake Mushroom

Recorded for Shiitake Mushroom in the same Natural Medicines adverse-effect record shown under Wheezing above.

Levothyroxine

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›
An allergic reaction Worth acting on Additional detail
Shiitake Mushroom
“Orally, shiitake mushrooms can cause shiitake dermatitis, a skin eruption that resembles whiplash marks, usually found on the trunk and limbs. This dermatitis is thought to be a toxic response to lentinan or other compounds found normally in uncooked or inadequately cooked shiitake mushroom. The rash can be made worse by scratching.”

Shiitake Mushroom · Natural Medicines adverse-effect record, reported in dermatitis.
6 sources cited

1148. Hanada K, Hashimoto I. Flagellate mushroom (Shiitake) dermatitis and photosensitivity. Dermatol 1998;197:255-7. PubMed

1152. Nakamura T. Shiitake (Lentinus edodes) dermatitis. Contact Dermatitis 1992;27:65-70.

74782. Lippert, U., Martin, V., Schwertfeger, C., Junghans, V., Ellinghaus, B., and Fuchs, T. Shiitake dermatitis. Br.J Dermatol. 2003;148(1):178-179.

74806. Mak, R. K. and Wakelin, S. H. Shiitake dermatitis: the first case reported from a European country. Br J Dermatol 2006;154(4):800-801. PubMed

94236. Ade R, Sukut C, Wiser HJ, Shockman S, Buescher L. Shiitake dermatitis demonstrating Köebner phenomenon. Int J Dermatol. 2015;54(5):e179-81.

94237. Adler MJ, Larsen WG. Clinical variability of shiitake dermatitis. J Am Acad Dermatol. 2012 Oct;67(4):e140-1. PubMed
Levothyroxine

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›
Fever / Itching Additional detail

Shiitake Mushroom

Recorded for Shiitake Mushroom in the same Natural Medicines adverse-effect record shown under An allergic reaction above.

Levothyroxine

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›
Tiredness Additional detail
Shiitake Mushroom
“In patients experiencing shiitake dermatitis, other symptoms may include prickling in the hands. Malaise has also been reported following oral intake or contact.

Orally, the shiitake mushroom extract AHCC has been reported to cause mild and transient headache.”

Shiitake Mushroom · Natural Medicines adverse-effect record, reported in cluster headache.
4 sources cited

94256. Nguyen AH, Gonzaga MI, Lim VM, Adler MJ, Mitkov MV, Cappel MA. Clinical features of shiitake dermatitis: a systematic review. Int J Dermatol. 2017 Jun;56(6):610-616. PubMed

1151. Matsui S, Nakazawa T, Umegae Y, Mori M. Hypersensitivity pneumonitis induced by Shiitake mushroom spores. Intern Med 1992;31:1204-6.

94240. Baran W, Batycka-Baran A, Maj J, Szepietowski JC. Shiitake dermatitis - now also in Poland. Acta Derm Venereol. 2015 Jan;95(1):102-3. PubMed

30365. Spierings, E. L., Fujii, H., Sun, B., and Walshe, T. A Phase I study of the safety of the nutritional supplement, active hexose correlated compound, AHCC, in healthy volunteers. J Nutr Sci Vitaminol.(Tokyo) 2007;53(6):536-539. PubMed
Levothyroxine

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›
Diarrhea Additional detail

Shiitake Mushroom

“Orally, shiitake mushroom is generally well tolerated when cooked and consumed as a food.

Most Common Adverse Effects:

Orally: Abdominal discomfort, bloating, diarrhea, nausea, and vomiting.

Serious Adverse Effects (Rare):

Orally: Consumption of raw shiitake mushroom can cause shiitake dermatitis, a skin eruption resembling whiplash marks which can be accompanied by systemic symptoms.”

Shiitake Mushroom · Natural Medicines adverse-effect record, reported in dermatitis.

Levothyroxine

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›
A skin rash Additional detail

Shiitake Mushroom

Recorded for Shiitake Mushroom in the same Natural Medicines adverse-effect record shown under Diarrhea above.

Levothyroxine

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›
Vomiting Additional detail
Shiitake Mushroom
“Orally, shiitake mushrooms can cause abdominal discomfort, including bloating, nausea, pain, vomiting, and diarrhea. Gastrointestinal symptoms, such as diarrhea, problems swallowing, or mouth ulcers have been associated with shiitake dermatitis.”

Shiitake Mushroom · Natural Medicines adverse-effect record, reported in dermatitis.
6 sources cited

1149. Levy AM, Kita H, Phillips SF, et al. Eosinophilia and gastrointestinal symptoms after ingestion of shiitake mushrooms. J Allergy Clin Immunol 1998;101:613-20. PubMed

30365. Spierings, E. L., Fujii, H., Sun, B., and Walshe, T. A Phase I study of the safety of the nutritional supplement, active hexose correlated compound, AHCC, in healthy volunteers. J Nutr Sci Vitaminol.(Tokyo) 2007;53(6):536-539. PubMed

30375. Sumiyoshi, Y., Hashine, K., Kakehi, Y., Yoshimura, K., Satou, T., Kuruma, H., Namiki, S., and Shinohara, N. Dietary administration of mushroom mycelium extracts in patients with early stage prostate cancers managed expectantly: a phase II study. Jpn.J Cl PubMed

30419. Thaiudom, S., Piyaniran, W., and Chutaputthi, A. A study of the efficacy of Active Hexose Correlated Compound (AHCC) in the treatment of chronic Hepatitis C patients at Phramongkutklao Hospital. The Medical News (Thailand) 2010;325:13-16.

94241. Boels D, Landreau A, Bruneau C, et al. Shiitake dermatitis recorded by French Poison Control Centers - new case series with clinical observations. Clin Toxicol (Phila). 2014 Jul;52(6):625-8. PubMed

94256. Nguyen AH, Gonzaga MI, Lim VM, Adler MJ, Mitkov MV, Cappel MA. Clinical features of shiitake dermatitis: a systematic review. Int J Dermatol. 2017 Jun;56(6):610-616. PubMed
Levothyroxine

Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›

Showing the 10 most notable of 12 shared effects — ranked by how unusual each one is, not just whether both lists mention it.

Reported for Shiitake Mushroom but not commonly for Levothyroxine: sun sensitivity, stomach upset, mouth irritation or sores and a bowel blockage.

Effects for Levothyroxine come from the ADVERSE REACTIONS section of its FDA label; effects for Shiitake Mushroom come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Levothyroxine Products Have a Food Rule — Shiitake Mushroom Should Not Break It

At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach. Most supplements — Shiitake Mushroom included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Levothyroxine on its own and move Shiitake Mushroom to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Levothyroxine products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Overlapping uses

What Levothyroxine Is Prescribed For, and What Shiitake Mushroom Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Levothyroxine is a prescription medicine with approved uses on its FDA label. Shiitake Mushroom is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Levothyroxine is prescribed for: Levothyroxine replaces or supplements the thyroid hormone your body isn't making enough of. It's used for hypothyroidism — an underactive thyroid — in adults, children, and even newborns, whether the cause is the thyroid gland itself, the pituitary gland, or the hypothalamus in the brain. It's also used alongside surgery and radioiodine treatment in people with certain types of thyroid cancer, to help suppress the hormone that can stimulate cancer growth. It is not meant for weight loss, treating benign thyroid nodules in people who have enough iodine, or for hypothyroidism during recovery from a temporary condition called subacute thyroiditis.

Shiitake Mushroom has been studied for:

Cancer studied, not established Shiitake Mushroom has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

Shiitake Mushroom for cancer

It is unclear if oral shiitake mushroom is beneficial in patients with cancer.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Levothyroxine on your own; if you are taking Shiitake Mushroom for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Shiitake Mushroom or Levothyroxine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Shiitake Mushroom or Levothyroxine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Levothyroxine

This page covers Shiitake Mushroom only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levothyroxine page lists 50 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Tiratricol (major), Acetyl-l-carnitine (moderate), Alpha-lipoic Acid (moderate) and Ascophyllum Nodosum (moderate).

By severity: 2 major · 39 moderate · 9 minor.

From our pharmacist’s overview on the Levothyroxine page

“Levothyroxine replaces a hormone your body measures in tiny amounts, so small shifts in its blood level show up in how you feel, and I treat this list with genuine care. Nearly everything on it does one of two things: blocks the pill from being absorbed in the gut, the way everyday minerals like calcium do by binding it into complexes,…”

Reviewed by 2 · Jul 18, 2026

Open the Levothyroxine interaction page

One more smart check

Taking Shiitake Mushroom as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,613 real supplement products containing Shiitake Mushroom, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Shiitake Mushroom. Even though Shiitake Mushroom itself has no known interaction with Levothyroxine, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Shiitake Mushroom and Levothyroxine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Shiitake Mushroom

Top 25%

#178 of 1,452 supplements looked up here in the last 7 days

29 days ago today

Medication Levothyroxine

Top 10

#2 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Shiitake Mushroom reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Shiitake Mushroom and Levothyroxine records this page draws on were last updated July 10, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Shiitake Mushroom

What is Shiitake Mushroom?

Immune support
General wellness and nutrition
Cholesterol and heart health
Adjunct in cancer care (lentinan, AHCC)
Antioxidant support

Shiitake is a popular edible mushroom that is nutritious and safe to eat as food for most people. Some of its extracts (like lentinan and AHCC) have been studied as immune support, mainly alongside cancer treatment, but evidence for most supplement uses is limited. Talk with your pharmacist or doctor before using concentrated shiitake supplements.

Lentinula edodes · Omphalotaceae · Fruiting body (mushroom cap and stem); mycelium extracts · Whole food (fresh or dried mushrooms), capsules, tablets, powders, liquid extracts, and standardized extracts such as lentinan and AHCC

An interaction check asks whether these two react with each other — it does not ask whether Shiitake Mushroom is a good idea for someone in your situation. Here is what our Shiitake Mushroom record says about it on its own.

Shiitake Mushroom: dosing

There is no official standardized dose for shiitake supplements, and products vary widely in strength and form. Some research used specialized extracts (like lentinan given by injection in a medical setting), which is very different from over-the-counter capsules.If you choose a shiitake supplement, follow the directions on the product label and do not exceed the recommended amount.

From our Shiitake Mushroom monograph — the full record covers uses, side effects and every documented interaction.

Read the full Shiitake Mushroom monograph & all interactions

Medication

About Levothyroxine

What Is Levothyroxine Used For?

Brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, Levo-T, Eltroxin, Estre, Levothyroxine, Novothyrox, Levolet

Levothyroxine replaces or supplements the thyroid hormone your body isn't making enough of. It's used for hypothyroidism — an underactive thyroid — in adults, children, and even newborns, whether the cause is the thyroid gland itself, the pituitary gland, or the hypothalamus in the brain.

It's also used alongside surgery and radioiodine treatment in people with certain types of thyroid cancer, to help suppress the hormone that can stimulate cancer growth. It is not meant for weight loss, treating benign thyroid nodules in people who have enough iodine, or for hypothyroidism during recovery from a temporary condition called subacute thyroiditis.

See full Levothyroxine drug information

Keep checking

Other Drugs & Shiitake Mushroom

Browse every other medication we’ve checked against Shiitake Mushroom — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major

312Moderate

0Minor

2,517No known interaction

312 Moderate 2,517 No interaction

Moderate

312 interactions

Showing 60 of 312 moderate interactions — see all 312 on the Shiitake Mushroom page.

No interaction 2,517 drugs checked — show the list

We also checked Shiitake Mushroom against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,517 medications checked with no known interaction — see the full Shiitake Mushroom list.

See the full Shiitake Mushroom interactions page

See every supplement checked against Levothyroxine, ranked by severity

Evidence & sources

Shiitake Mushroom References

The 67 references that drive our Shiitake Mushroom monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Hitosugi M, Kitamura O, Takatsu A, Yoshino Y. Autopsy case of duodenal obstruction from impacted mushroom. J Gastroenterol 1998;33:562-5. PubMed
Hanada K, Hashimoto I. Flagellate mushroom (Shiitake) dermatitis and photosensitivity. Dermatol 1998;197:255-7. PubMed
Levy AM, Kita H, Phillips SF, et al. Eosinophilia and gastrointestinal symptoms after ingestion of shiitake mushrooms. J Allergy Clin Immunol 1998;101:613-20. PubMed
Murakami M, Kawabe K, Hosoi Y, et al. Decreased pulmonary perfusion in hypersensitivity pneumonitis caused by Shiitake mushroom spores. J Intern Med 1997;241:85-8. PubMed
Matsui S, Nakazawa T, Umegae Y, Mori M. Hypersensitivity pneumonitis induced by Shiitake mushroom spores. Intern Med 1992;31:1204-6.
Nakamura T. Shiitake (Lentinus edodes) dermatitis. Contact Dermatitis 1992;27:65-70.
Ueda A, Obama K, Aoyama K, et al. Allergic contact dermatitis in shiitake (Lentinus edodes (Berk) Sing) growers. Contact Dermatitis 1992;26:228-33.
Burikhanov, R. B., Wakame, K., Igarashi, Y., Wang, S., and Matsuzaki, S. Suppressive effect of active hexose correlated compound (AHCC) on thymic apoptosis induced by dexamethasone in the rat. Endocr.Regul. 2000;34(4):181-188.
Gao, Y., Zhang, D., Sun, B., Fujii, H., Kosuna, K., and Yin, Z. Active hexose correlated compound enhances tumor surveillance through regulating both innate and adaptive immune responses. Cancer Immunol.Immunother. 2006;55(10):1258-1266. PubMed
Ritz, B. W., Nogusa, S., Ackerman, E. A., and Gardner, E. M. Supplementation with active hexose correlated compound increases the innate immune response of young mice to primary influenza infection. J Nutr. 2006;136(11):2868-2873. PubMed
Aviles, H., O'Donnell, P., Sun, B., and Sonnenfeld, G. Active hexose correlated compound (AHCC) enhances resistance to infection in a mouse model of surgical wound infection. Surg.Infect.(Larchmt.) 2006;7(6):527-535. PubMed
Spierings, E. L., Fujii, H., Sun, B., and Walshe, T. A Phase I study of the safety of the nutritional supplement, active hexose correlated compound, AHCC, in healthy volunteers. J Nutr Sci Vitaminol.(Tokyo) 2007;53(6):536-539. PubMed
Aviles, H., O'Donnell, P., Orshal, J., Fujii, H., Sun, B., and Sonnenfeld, G. Active hexose correlated compound activates immune function to decrease bacterial load in a murine model of intramuscular infection. Am J Surg. 2008;195(4):537-545. PubMed
Ritz, B. W. Supplementation with active hexose correlated compound increases survival following infectious challenge in mice. Nutr.Rev. 2008;66(9):526-531. PubMed
Terakawa, N., Matsui, Y., Satoi, S., Yanagimoto, H., Takahashi, K., Yamamoto, T., Yamao, J., Takai, S., Kwon, A. H., and Kamiyama, Y. Immunological effect of active hexose correlated compound (AHCC) in healthy volunteers: a double-blind, placebo-controll
Mach, C. M., Fugii, H., Wakame, K., and Smith, J. Evaluation of active hexose correlated compound hepatic metabolism and potential for drug interactions with chemotherapy agents. J Soc Integr.Oncol. 2008;6(3):105-109.
Wang, S., Welte, T., Fang, H., Chang, G. J., Born, W. K., O'Brien, R. L., Sun, B., Fujii, H., Kosuna, K., and Wang, T. Oral administration of active hexose correlated compound enhances host resistance to West Nile encephalitis in mice. J Nutr. 2009;139(3 PubMed
Sumiyoshi, Y., Hashine, K., Kakehi, Y., Yoshimura, K., Satou, T., Kuruma, H., Namiki, S., and Shinohara, N. Dietary administration of mushroom mycelium extracts in patients with early stage prostate cancers managed expectantly: a phase II study. Jpn.J Cl PubMed
Yin, Z., Fujii, H., and Walshe, T. Effects of active hexose correlated compound on frequency of CD4+ and CD8+ T cells producing interferon-gamma and/or tumor necrosis factor-alpha in healthy adults. Hum.Immunol. 2010;71(12):1187-1190.
Lee, W. W., Lee, N., Fujii, H., and Kang, I. Active Hexose Correlated Compound promotes T helper (Th) 17 and 1 cell responses via inducing IL-1beta production from monocytes in humans. Cell Immunol. 2012;275(1-2):19-23.
Daddaoua, A., Martinez-Plata, E., Ortega-Gonzalez, M., Ocon, B., Aranda, C. J., Zarzuelo, A., Suarez, M. D., de Medina, F. S., and Martinez-Augustin, O. The nutritional supplement Active Hexose Correlated Compound (AHCC) has direct immunomodulatory actio
Roman, B. E., Beli, E., Duriancik, D. M., and Gardner, E. M. Short-term supplementation with active hexose correlated compound improves the antibody response to influenza B vaccine. Nutr Res. 2013;33(1):12-17. PubMed
Uno, K., Kosuna, K., Sun, B., Fujii, H., Wakame, K., Chikumaru, S., Hosokawa, G., and Ueda, Y. Active Hexose Correlated Compound (AHCC) Improves Immunological Parameters and Performance Status of Patients with Solid Tumors. Biotherapy 2000;14(3):303-309.
Ghoneum, M., Wimbley, M., Salem, F., McKlain, A., Attallah, N., and Gill, G. Immunomodulatory and anticancer effects of active hexose correlated compound (AHCC). Int J Immunother 1995;11:23-28.
Thaiudom, S., Piyaniran, W., and Chutaputthi, A. A study of the efficacy of Active Hexose Correlated Compound (AHCC) in the treatment of chronic Hepatitis C patients at Phramongkutklao Hospital. The Medical News (Thailand) 2010;325:13-16.
Smith, J. A., Hunter, R. J., Fujii, H., Wakame, K., and Wolf, J. Defining Synergistic Activity ofthe Combination of Active Hexose Correlated Compound (AHCC) with Liposomal Doxorubicin (Doxil). Presented at the 18th International Congress on Nutrition and
Sia, G. M. and Candlish, J. K. Effects of shiitake (Lentinus edodes) extract on human neutrophils and the U937 monocytic cell line. Phytother.Res. 1999;13(2):133-137. DOI
Fujiwara, K., Sato, T., Yonei, T., Genba, K., Nogami, N., and Yamadori, I. [A case of chronic hypersensitivity pneumonitis induced by shiitake mushroom spores]. Nihon Kokyuki.Gakkai Zasshi 2000;38(12):908-913.
Lippert, U., Martin, V., Schwertfeger, C., Junghans, V., Ellinghaus, B., and Fuchs, T. Shiitake dermatitis. Br.J Dermatol. 2003;148(1):178-179.
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Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Shiitake Mushroom and Levothyroxine Together: Common Questions

Is it safe to take Shiitake Mushroom with Levothyroxine?

We do not list a known interaction between Shiitake Mushroom and Levothyroxine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

Do Shiitake Mushroom and Levothyroxine have any of the same side effects?

Yes — our sources link each of them separately to 10 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.

Should I take Shiitake Mushroom and Levothyroxine at the same time of day?

At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Levothyroxine on its own and move Shiitake Mushroom to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.

Are Shiitake Mushroom and Levothyroxine used for the same thing?

They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Shiitake Mushroom in each. That is a conversation for your prescriber, especially if Levothyroxine is being adjusted to a target.

How was the Shiitake Mushroom and Levothyroxine combination checked?

Interactions in our licensed database are recorded against drug classes. Levothyroxine is filed under 3 classifications, and Shiitake Mushroom has documented interactions with 2 drug classes — none of Levothyroxine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Shiitake Mushroom interact with any other medications?

Yes. Shiitake Mushroom has 312 documented drug interactions in our database — Levothyroxine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Levothyroxine interact with any supplements?

Yes. Levothyroxine has documented interactions with 50 supplements in our database — Shiitake Mushroom is not one of them. The Levothyroxine interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.