- Ling zhi
- Lin zi
- Mushroom of immortality
For Patients & Caregivers
How It Works
Reishi mushroom has antioxidant properties and may enhance immune response.
Reishi mushroom contains complex sugars known as beta-glucans. Lab studies suggest that these compounds may help stop the growth and spread of cancer cells. When animals were fed beta-glucans, some cells of their immune system became more active.
Limited data from clinical studies suggest reishi can strengthen immune response in humans. In addition, reishi mushrooms contain sterols that can act as precursors to hormones in the body, along with substances called triterpenes that may have blood pressure-lowering and anti-allergy effects. Reishi mushrooms have also been shown to slow blood clotting.
Reishi mushroom can cause toxicity in some immune cells. There are also a few documented cases of liver toxicity. More studies are needed to show that reishi is safe and effective for use with cancer treatment.
- To treat fatigue
No scientific evidence supports this use.
- To lower high cholesterol
In one small study, a reishi mushroom product increased HDL-cholesterol level in patients with borderline elevations of cholesterol.
- To treat HIV and AIDS
Laboratory studies suggest that reishi mushroom may stimulate certain cells of the immune system, but evidence is lacking on reishi’s ability fight infections.
- To lower high blood pressure
Laboratory studies suggest that reishi mushroom may lower blood pressure. Human studies are lacking.
- To stimulate the immune system
Laboratory studies suggest that reishi mushroom may stimulate some cells of the immune system. A small clinical trial showed that reishi can enhance immune response in advanced-stage cancer patients. More studies are needed.
- To reduce inflammation
Laboratory studies suggest that reishi mushroom may have antihistamine effects. This has not been tested in humans.
- For increased strength and stamina
No scientific evidence supports this use.
- To treat lower urinary tract symptoms (LUTS)
One study suggests that reishi extracts may improve urinary flow in men with slight-to-moderate LUTS. Larger, long-term studies are needed to see if it can improve LUTS in men who have more severe symptoms.
Do Not Take If
- You are taking warfarin or other blood thinners: Reishi may increase the risk of bleeding.
- You are undergoing chemotherapy: Reishi may make some chemotherapy drugs less effective.
- You are taking immunosuppressants: Reishi can stimulate immune responses.
- You are taking cytochrome P450 2E1, 1A2, and 3A substrate drugs: Reishi may increase the risk of side effects of these drugs.
Nausea and insomnia have been reported in a few patients.
- Liver toxicity: In two cases with the use of powdered reishi mushroom, one of which resulted in death.
- Chronic diarrhea: In a 49-year-old man with non-Hodgkin’s lymphoma following long-term use of a powdered reishi mushroom extract.
- Treatment error: A long-term user of reishi mushrooms was mistakenly treated for a parasite that in lab specimens appears similar in structure to reishi mushroom.
For Healthcare Professionals
Reishi mushroom is a fungus that holds an important place in the traditional medical systems of China, Japan, Korea and other Asian countries for its health-promoting effects. It is used as an immunostimulant by patients with HIV and cancer. The active constituents include both beta-glucan polysaccharides and triterpenes.
Extracts of reishi were shown to have immunomodulatory (2) (3) (4) (5) (12), renoprotective (9), anti-inflammatory (36), and hepatoprotective (37) properties both in vitro and in vivo. Clinical studies indicate its benefits in improving lower urinary tract symptoms (LUTS) in men (10) (20), and in exerting mild antidiabetic effects and improving dyslipidemia (29). However, randomized controlled trials do not support the use of reishi to address cardiovascular risk factors associated with type 2 diabetes (38) (43). A pilot study of reishi spore powder did not find it helpful in treating patients with Alzheimer’s disease (AD) (1).
Reishi has also been studied for its anticancer potential. In vitro and animal studies indicate that it has antiproliferative (39) and chemopreventive effects (21), alleviates chemotherapy-induced nausea (13), enhances the efficacy of radiotherapy (22), and increases the sensitivity of ovarian cancer cells to cisplatin (27). It may also help prevent cisplatin-induced nephrotoxicity (28).
In small clinical studies, reishi increased plasma antioxidant capacity (6) (7), and enhanced immune responses in cancer patients (8) (40). In another study, a water-soluble reishi extract appeared to suppress development of colorectal adenomas (41). Remission of hepatocellular carcinoma was reported in a few cases in a single study (23). Another case series suggests a dietary supplement containing Reishi mushroom spores may have a negative effect on gastrointestinal cancer patients (42). Currently, there is no evidence for the use of reishi in first-line cancer treatment or to prolong long-term cancer survival. However, it may have a role in stimulating host immunity and enhancing tumor response (44).
An in vitro study reported that reishi mushroom extract has toxic effects in leukocytes (14). There are also a few documented cases of hepatotoxicity (24) (25). More research is therefore needed to determine its safety and effectiveness as an adjunctive cancer treatment.
Mechanism of Action
Beta glucans, polysaccharides present in reishi, have demonstrated antitumor and immunostimulating activities (18) (40). Its triterpene compounds may inhibit tumor invasion by reducing matrix metalloproteinase expression (16), and tumor metastases by limiting attachment to endothelial cells (17). Recent findings indicate that reishi induces natural killer (NK) cell cytotoxicity against various cancer cell lines via activation of the natural cytotoxic receptors (NKG2D/NCR) and mitogen-activated protein kinase (MAPK)-signaling pathways, which result in exocytosis of perforin and granulysin (31). Reishi polysaccharides were also shown to increase expression of the major histocompatibility (MHC) class I and costimulatory molecules on melanoma cells, resulting in enhanced antitumor cytotoxicity (32). In human ovarian cancer cells, reishi inhibits proliferation by suppressing vascular endothelial growth factor (VEGF) expression and upregulating connexin 43 expression (39).
In other studies reishi increased plasma antioxidant capacity (6) (7) and enhanced immune response in advance-stage cancer patients (8). Its extracts also inhibited 5-alpha reductase, an important enzyme that converts testosterone to dihydrotestosterone and is upregulated in benign prostatic hyperplasia (9).
- Hepatoxicity: Two cases with the use of powdered reishi mushroom, leading to death in one instance (24) (25).
- Chronic diarrhea: In a 49-year-old man with non-Hodgkin’s lymphoma following prolonged consumption of powdered reishi mushroom extract (26).
- Pseudoparasitosis: Due to similarity in structure with Clonorchis sinensis ova, in a patient with a history of long-term ingestion of reishi mushrooms (39).
- Anticoagulants / Antiplatelets: Reishi may increase the risk of bleeding (12).
- Immunosuppressants: Reishi can enhance immune response (8).
- Chemotherapeutic agents: Reishi can increase plasma antioxidant capacity, and in theory can interact with chemotherapeutic agents that rely on free radicals (6).
- Cytochrome P450 substrates: Reishi polysaccharides inhibit CYP2E1, CYP1A2, and CYP3A, and can affect the intracellular concentration of drugs metabolized by these enzymes (15).