Agaricus
Agaricus subrufescens (syn. A. blazei Murill, A. brasiliensis)
Agaricus blazei ('almond mushroom', 'sun mushroom') is a beta-glucan-rich Brazilian mushroom studied mainly in Japan and Brazil for immune support alongside cancer therapy, with promising but small trials and a documented liver-toxicity signal in cancer patients.
At a Glance
- Best known for
- Increased natural killer cell activity and quality of life in a trial of gynecologic cancer patients on chemotherapy, Immune modulation (beta-glucans, proteoglycans), Improved glucose and insulin sensitivity in a small type 2 diabetes trial
- Evidence
- Preliminary
- Typical dose
- 1.5–3 g dried mushroom powder daily
- Type
- Mushroom
What is Agaricus?
Agaricus subrufescens, long marketed as Agaricus blazei Murill (ABM), is an edible mushroom with an almond-like aroma native to the grasslands of southeastern Brazil, where villagers in Piedade reportedly had low rates of chronic disease, a claim that inspired Japanese research from the 1960s onward. It is now cultivated in Japan, China, Brazil and the US and sold as 'Himematsutake', 'cogumelo do sol' or 'royal sun agaricus'. Taxonomy has been confused: the Brazilian commercial strain is now recognized as A. subrufescens, a species also found in North America and Europe. It is one of the most widely used complementary cancer supplements in Japan and Brazil, where it has been the subject of both hopeful clinical studies and regulatory warnings.
Known Health Benefits
How It Works
Agaricus beta-glucans and proteoglycan complexes bind dectin-1, complement receptor 3 and Toll-like receptors on macrophages, dendritic cells and natural killer cells, increasing phagocytosis, NK cytotoxicity and production of interferon-γ and IL-12, which shifts immune balance toward a Th1 antitumor response. Some fractions also promote apoptosis in cancer cell lines and inhibit angiogenesis in animal models. In the gut, the polysaccharides act as prebiotics and reduce inflammatory cytokines, the mechanism proposed in ulcerative colitis and hepatitis pilot studies. Beta-glucans and other components improve insulin sensitivity in rodents and in one human trial by increasing adiponectin. Agaritine, a hydrazine compound present in Agaricus species including the common button mushroom, is largely destroyed by cooking and extraction.
What Research Says
Human studies are few and small. The most cited is a 2004 Korean randomized trial of 100 women with cervical, ovarian or endometrial cancer on chemotherapy: those taking an Agaricus extract had higher natural killer cell activity and reported better appetite, hair loss, emotional stability and general weakness than placebo, though tumor response did not differ. A 2011 Norwegian placebo-controlled trial of 50 patients with ulcerative colitis or Crohn's disease found reduced inflammatory cytokines and improved symptom scores with an Agaricus-based extract. A small 2007 trial in type 2 diabetes reported improved insulin resistance with 1.5 g extract daily for 12 weeks. Pilot studies in hepatitis B and C reported lowered liver enzymes. Balanced against this, Japanese authorities reported cases of severe hepatic dysfunction, including a death, in cancer patients taking Agaricus products, and in 2006 Japan's Ministry of Health ordered a product withdrawn after animal carcinogenicity testing. A 2008 review concluded that Agaricus deserves more research but cannot be recommended as self-treatment, particularly in people with liver impairment.
Active Compounds
Beta-(1,3)/(1,6)-glucans, α-glucans, proteoglycans, ergosterol, agaritine (hydrazine derivative), blazeispirols, linoleic acid
Forms & Bioavailability
Beta-glucans are not absorbed intact; they act on gut immune tissue and are partially taken up by intestinal macrophages, which transport fragments to the bone marrow and spleen over several days. Hot-water extraction improves the availability of polysaccharides compared with raw powder, and products standardized to beta-glucan content are preferable to those listing 'polysaccharides' (which may include starch). Cooking or extraction also reduces agaritine substantially. Effects on immune markers in trials appeared within 2–6 weeks of daily dosing.
Dosage Guidance
| Use Case | Dosage |
|---|---|
| Immune support (general) | 1.5–3 g dried mushroom powder daily |
| Adjunct during cancer therapy (trial dose) | 1.5 g standardized extract 2x daily |
| Type 2 diabetes (pilot trial) | 500 mg extract 3x daily |
| Hot-water extract | 500–1000 mg 1–2x daily |
Always consult a healthcare provider for personalized dosing.
Natural Food Sources
- Fresh or dried Agaricus blazei mushrooms (cooked; almond flavor)
- Mushroom teas and broths (traditional Brazilian preparation)
- Button mushrooms (Agaricus bisporus) are a related but different species
Potential Side Effects
Generally mild (nausea, diarrhea, itching); several cases of severe liver injury and one fatality in Japanese cancer patients taking Agaricus extracts; agaritine content raises theoretical (not proven) carcinogenicity concern with heavy raw intake; allergic reactions
Who Should Avoid It
- Liver disease, elevated liver enzymes, or use of hepatotoxic drugs
- Pregnancy and breastfeeding (no safety data)
- Mushroom allergy
- Autoimmune disease on immunosuppressants (theoretical immune activation)
- Diabetes on insulin or sulfonylureas without glucose monitoring
Pregnancy & Lactation
There are no safety data for Agaricus supplements in pregnancy or lactation. Given the liver toxicity reports and agaritine content, extracts should be avoided in both. Eating the cooked mushroom occasionally as food is unlikely to be a problem but has not been specifically studied.
Known Drug Interactions
May enhance effects of diabetes medications (hypoglycemia); theoretical interaction with immunosuppressants and with anticoagulants; may interfere with liver-metabolized chemotherapy agents; caution with other hepatotoxic drugs
Evidence Classification
Based on in vitro studies, animal models, pilot trials, or traditional use documentation. Clinical evidence is limited.
Frequently Asked Questions
Is Agaricus blazei a cancer cure?
No. The best trial found it improved immune markers and quality of life in women on chemotherapy but did not change how the tumors responded. Animal studies show antitumor effects, but these have not translated into proven benefit in people. It is studied as a supportive therapy, never as a replacement for cancer treatment, and must be discussed with the treating oncologist.
What is the liver safety concern?
Japanese case reports describe acute liver failure in cancer patients taking Agaricus products, with one death, and the mechanism is unclear (possibly contaminants, high doses, or interaction with chemotherapy). A 2008 review concluded it should not be used by people with impaired liver function. If you take it, baseline and periodic liver enzyme tests are prudent, and stop immediately if you develop jaundice or dark urine.
What is agaritine and should I worry about it?
Agaritine is a hydrazine compound found in Agaricus mushrooms, including ordinary button mushrooms. It is mutagenic in some lab tests, but human studies of button mushroom consumption have not shown cancer risk, and cooking and extraction destroy most of it. The practical takeaway is to use cooked mushrooms or processed extracts rather than large amounts of raw powder.
How does Agaricus compare with reishi or turkey tail?
All three are beta-glucan mushrooms with immune-modulating effects. Turkey tail (PSK/PSP) has the largest body of cancer-adjunct trials, particularly in Japan; reishi has several trials and a Cochrane review; Agaricus has fewer, smaller studies and a liver safety signal. For general immune support, reishi or turkey tail are better-characterized choices.
References
- Natural killer cell activity and quality of life were improved by consumption of a mushroom extract, Agaricus blazei Murill Kyowa, in gynecological cancer patients undergoing chemotherapy. Ahn WS, Kim DJ, Chae GT, et al.. Int J Gynecol Cancer (2004)
- The Medicinal Mushroom Agaricus blazei Murrill: Review of Literature and Pharmaco-Toxicological Problems. Firenzuoli F, Gori L, Lombardo G. Evid Based Complement Alternat Med (2008)
- Effects of the medicinal mushroom Agaricus blazei Murill on immunity, infection and cancer. Hetland G, Johnson E, Lyberg T, Bernardshaw S, Tryggestad AM, Grinde B. Scand J Immunol (2008)
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This entry is for educational purposes only. It is not medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you take medications or have health conditions.