Agaricus blazei Murill, commonly known in Japan as Himematsutake or the “God’s mushroom,” is a basidiomycete fungus native to the Atlantic Forest region of Brazil that has attracted considerable scientific interest since its introduction to Japanese researchers in the 1960s. Unlike more widely marketed functional mushrooms such as reishi or lion’s mane, Agaricus blazei remains relatively obscure in Western supplement markets, yet a growing body of peer-reviewed research suggests it may carry meaningful biological activity, particularly in the area of immune function and inflammatory regulation.
What Is Agaricus Blazei Murill?
Agaricus blazei belongs to the same genus as the common button mushroom (Agaricus bisporus) but is distinguished by a notably high concentration of beta-glucans, a class of soluble dietary fiber known to interact with pattern recognition receptors in the human immune system. The fruiting body contains both beta-1,3-glucan and beta-1,6-glucan chains, and its polysaccharide fraction has been the subject of numerous preclinical and a smaller number of clinical investigations.
In Japan, Himematsutake preparations have been used as dietary supplements alongside conventional oncology care for several decades, and this clinical tradition provided an early rationale for more controlled research into its immune-modulating properties.
Immune Modulation: What the Research Shows
The most studied biological activity of Agaricus blazei relates to its effects on immune cell populations. Several lines of evidence suggest that polysaccharide fractions from the mushroom may activate or modulate natural killer (NK) cells, macrophages, and dendritic cells, all components of the innate immune response.
A 2016 study published in Innate Immunity examined how water and ethanol extracts from various medicinal mushrooms, including Agaricus blazei, affected NK cell-mediated cytotoxicity. The researchers found that the mushroom extracts demonstrated immunomodulatory properties, with the specific extract preparation influencing the degree of NK cell activity observed.[1] While these findings are preliminary and based on cell-based models, they provide a mechanistic rationale for ongoing investigation.
A separate study in Immunology (2015) explored how Agaricus blazei polysaccharides influenced myeloid-derived suppressor cells (MDSCs), a population of immune cells that can suppress anti-tumor responses in certain contexts. The researchers found that polysaccharide fractions appeared to shift MDSC function via Toll-like receptor 2 signaling, promoting a more pro-inflammatory, M1-type macrophage profile.[2] This type of immune reprogramming is an area of active interest in immunology, though the authors noted the findings were in animal and cell models and require further validation in humans.
A Pilot Human Trial
One of the more methodologically rigorous human studies available comes from a 2025 randomized, double-blind, placebo-controlled multicenter pilot trial published in Biomedicines. The study enrolled 66 patients undergoing curative surgical resection for non-small-cell lung cancer (NSCLC), a population in which postoperative immune suppression is a known clinical concern. Participants received either a multivitamin and mineral complex containing Agaricus blazei or placebo for 28 days following surgery.
While the primary endpoint, recovery of NK cell activity, did not reach statistical significance, the treatment group demonstrated a numerically greater relative recovery (17.8% vs. 9.9%, p = 0.104). Significantly, immune profiling showed better preservation of T cell counts (p = 0.026) and B cell counts (p = 0.001) in the treatment group, along with a greater reduction in monocytes (p = 0.031).[3] The authors concluded that supplementation may contribute to favorable immune modulation in this context and called for larger long-term trials to confirm the observations. Importantly, the supplement used in this trial was a complex formula, meaning the effects cannot be attributed solely to Agaricus blazei.
Polysaccharide Research and the Tumor Microenvironment
Preclinical research has continued to explore the mechanisms by which Agaricus blazei Murill polysaccharide (ABMP) may influence immune responses in disease settings. A 2025 study in Molecular Nutrition and Food Research examined the anti-tumor efficacy of ABMP in a mouse model of colon cancer. Researchers found that polysaccharide supplementation may inhibit tumor growth through effects on the tumor microenvironment, specifically through modulation of lipid content in tumor tissue. Interestingly, the study identified age-dependent differences in efficacy, with younger animals showing a greater response.[4] The authors stressed that these are animal findings, and extrapolating them directly to human supplementation requires considerable caution.
Extract Preparation and Bioactive Variability
One challenge in interpreting the Agaricus blazei literature is that commercial preparations vary substantially in extraction method, part of the mushroom used (fruiting body vs. mycelium), and beta-glucan concentration. A 2021 study in the Journal of Fungi examined subcritical water extracts specifically from Agaricus blazei mycelium and found that this preparation inhibited the expression of immune checkpoint molecules in lung cancer cells in vitro, while also enhancing maturation markers in dendritic cells.[5] Subcritical water extraction is a relatively specialized technique, and findings from such preparations may not apply to standard hot-water or alcohol extracts commonly found in retail supplements.
Consumers evaluating Agaricus blazei products should note that certificate of analysis (CoA) documentation, including beta-glucan content verification, is an important quality indicator. For guidance on reading supplement labels, see our guide on beta-glucan vs. polysaccharide content on mushroom supplement labels.
Safety Considerations
In the available human trials, Agaricus blazei supplementation has generally been reported as well-tolerated at the doses studied. However, the evidence base remains limited in size and duration. Individuals taking immunosuppressive medications, those with autoimmune conditions, or those undergoing cancer treatment should consult a healthcare provider before adding any functional mushroom supplement, including Agaricus blazei, to their regimen. The immune-modulating properties that make this mushroom of scientific interest are the same properties that could theoretically interact with medical therapies designed to suppress or modulate immune activity.
Summary
Agaricus blazei Murill is a functional mushroom with a longer research history in Japan and Brazil than its relative obscurity in Western markets might suggest. The available evidence, while still largely preclinical, points toward meaningful beta-glucan-mediated immune activity, including effects on NK cells, macrophages, dendritic cells, and myeloid-derived suppressor cells. A small number of human trials indicate potential immune support in clinical populations, though larger studies are needed before strong conclusions can be drawn. As with other functional mushrooms, extract quality and preparation method appear to matter considerably for bioactivity.
References
- [1] Lu CC, et al. Immunomodulatory properties of medicinal mushrooms: differential effects of water and ethanol extracts on NK cell-mediated cytotoxicity. Innate Immun. 2016;22(7):522-33. PMID: 27469258
- [2] Liu Y, et al. Polysaccharide Agaricus blazei Murill stimulates myeloid derived suppressor cell differentiation from M2 to M1 type, which mediates inhibition of tumour immune-evasion via the Toll-like receptor 2 pathway. Immunology. 2015;146(3):379-91. PMID: 26194418
- [3] Kim J, et al. Immunomodulatory Effects of Multivitamin Complexes Containing Agaricus blazei in Patients Undergoing Curative Resection for Non-Small-Cell Lung Cancer. Biomedicines. 2025;14(1):53. PMID: 41595590
- [4] Xu Y, et al. The Age-Dependent Anticancer Efficacy of Agaricus blazei Murill Polysaccharide in Colon Cancer. Mol Nutr Food Res. 2025;69(5):e202400733. PMID: 39950425
- [5] Yasuma T, et al. Subcritical Water Extracts from Agaricus blazei Murrill’s Mycelium Inhibit the Expression of Immune Checkpoint Molecules and Axl Receptor. J Fungi (Basel). 2021;7(8):590. PMID: 34436128
Disclaimer: The information in this article is for educational purposes only and does not constitute medical advice. Functional mushroom supplements are not intended to diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare provider before starting any new supplement, especially if you are taking medications or managing a health condition.
