Benefits
A registered trial in people receiving chemotherapy for multiple myeloma (no results cited)
A trial in people with multiple myeloma receiving high-dose chemotherapy and a stem cell transplant gave a branded liquid mushroom extract (AndoSan) at 60 mL per day or placebo for about 7 weeks and measured immune signalling markers. No published results for it appear among this page's references, so it shows no benefit either way. It is also research in cancer patients under specialist care, not a reason for anyone else to take this mushroom.
Lung cancer surgery pilot: a combination product, and the main immune result was not significant
A pilot trial in 66 people having surgery for stage I to III non-small-cell lung cancer compared a multivitamin and mineral complex containing Agaricus blazei with placebo. Its headline immune measure, recovery of natural killer cells, was 17.8 percent versus 9.9 percent and was not statistically significant. Differences in T cells, B cells and monocytes were reported, but this was a small pilot and the product also contained vitamins and minerals, so nothing here can be credited to the mushroom.
NLRP3 inflammasome activation
This is a laboratory cell study, not a study in people: mushroom extracts increased IL-1beta and switched on an inflammation pathway in a human cell line grown in a dish. Cell studies suggest how something might work; they do not show that taking it does anything for you.
Studied in people with ulcerative colitis or Crohn's disease (single-group study of a different product)
People with ulcerative colitis or Crohn's disease took AndoSan, a different branded product, and several inflammatory markers fell compared with their own starting values. Everyone received the product, so with no placebo group the change cannot be attributed to the mushroom, and this study is not among the references listed on this page. It is worth noting that the mushroom looks inflammation-promoting in cell studies but inflammation-lowering here, which is one reason its immune effects are hard to predict.
Review of proposed mechanisms for a three-mushroom combination (lab and animal work)
A review discussing Agaricus blazei together with lion's mane and maitake describes proposed ways their beta-glucans might interact with immune cells. A review only summarises other work, the mechanisms described come mainly from cell and animal experiments, and none of it shows that this mushroom affects tumours or chemotherapy in people.
Beta-glucan-protein fraction tested in mice (preclinical)
A purified beta-glucan-protein fraction from the mushroom slowed a transplanted tumour in mice. This is an animal experiment with an isolated compound, it is not among the references listed on this page, and it says nothing about what a mushroom supplement does in people.
Honest framing — context-dependent immunomodulation
AbM differentially stimulates pro-inflammatory cytokine production in human monocytes and endothelial cells in vitro. However, oral intake in IBD patients reduces inflammatory cytokines in vivo. Pro-inflammatory in vitro versus immunosuppressive in vivo with oral intake, an important framing for autoimmune-condition caution and for understanding the apparent paradox between cellular and clinical findings.
Mechanism of action
β-(1→6)-D-glucan-protein complex (FIII-2-b)
A beta-glucan-protein fraction (FIII-2-b) isolated from this mushroom. In laboratory work it binds a receptor called Dectin-1 on immune cells, which is the proposed starting point for its immune effects.
NLRP3 inflammasome activation + IL-1β production
AbM water extracts activate the NLRP3 inflammasome in human THP-1 macrophages with IL-1beta production. Innate immune mechanism contributing to the cytokine effects.
Th1 cytotoxic cell + NK cell activation
In laboratory and animal work, beta-glucans can activate certain immune cells. In the one randomized human trial cited here, natural killer cell recovery did not differ significantly from placebo, so this remains a proposed mechanism rather than a demonstrated effect.
Anti-angiogenic and anti-metastatic effects
Laboratory and animal experiments have looked at whether mushroom compounds affect blood vessel growth around tumours. This is preclinical research only, and it does not apply to taking a supplement.
Chemotherapy enhancement and side-effect reduction
Animal and laboratory work suggested this mushroom might interact with chemotherapy, which is why a trial was designed in people with multiple myeloma. No human results supporting that idea are cited on this page, and mushroom supplements should never be combined with cancer treatment without an oncologist's approval.
Context-dependent immunomodulation (paradox resolution)
In cell studies the mushroom looks immune-stimulating, while in the small human studies of oral intake inflammatory markers went down. Why that happens is unknown. The practical point is that its immune effects are unpredictable, which matters if you have an autoimmune condition or take medicines that affect the immune system.
Clinical trials
Randomized double-blind phase 2 trial at Ullevaal University Hospital.
Clinical population described in trial publication.
A randomized, double-blind phase 2 trial in people with multiple myeloma who were receiving high-dose chemotherapy and a stem cell transplant, all under specialist cancer care. AndoSan™ AbM-based mushroom extract 60 mL/day for ~7 weeks vs placebo. It measured immune signalling markers and immune cell types. No published results from it are cited on this page, so it cannot be counted as evidence of any benefit.
Randomized double-blind placebo-controlled multicenter pilot in non-small-cell lung cancer perioperative immune modulation.
Clinical population described in trial publication.
Randomized double-blind placebo-controlled multicenter pilot in non-small-cell lung cancer perioperative immune modulation. It enrolled 66 people with stage I to III lung cancer and tested a multivitamin and mineral complex containing Agaricus blazei, not the mushroom alone. The main immune measure, natural killer cell recovery, was 17.8 percent versus 9.9 percent and was not statistically significant. Differences in T cells (P=0.026), B cells (P=0.001) and monocytes (P=0.031) were reported, but in a pilot this small they are preliminary and cannot be attributed to the mushroom.
A single-group study in patients with inflammatory bowel disease, using the branded AndoSan product, with no placebo comparison.
Clinical population described in trial publication.
Førland DT et al. 2011 (Scand J Immunol 73:66-75). People with ulcerative colitis or Crohn's disease took AndoSan, a different branded product, and several inflammatory markers were lower than at day 0. Everyone received the product and results were compared with their own starting values rather than a placebo group, so the change cannot be attributed to the mushroom. This paper is also not among the references listed on this page.