Evidence checked: 19 July 2026
Reishi is a woody mushroom used in traditional Chinese medicine and now sold as powders, capsules and concentrated extracts. Claims range from sleep and immune support to blood sugar control and cancer care. The important finding is less dramatic: laboratory research is extensive, but reliable human evidence for most claimed health effects remains limited.
A 2025 systematic review pooled 17 randomised trials involving 971 participants. Some small changes appeared in selected measures, but the certainty of evidence was very low for every assessed outcome. There were no significant pooled effects on blood pressure, fasting glucose, blood lipids, inflammatory markers or liver enzymes.[1] That means reishi mushroom benefits are not established treatments for those conditions.
This guide separates traditional use, biological activity and patient-important clinical outcomes. It also explains who should not take reishi without first speaking with a health professional.
Clinical bottom line: Reishi does not treat cancer and should not replace prescribed medicine. If you have cancer, liver disease, a bleeding disorder, an upcoming operation, or take anticoagulants, antiplatelets, immunosuppressants or chemotherapy, discuss any reishi product with your treating clinician and pharmacist before use.
Reishi mushroom identity, extracts and traditional use
Reishi commonly refers to Ganoderma lucidum or closely related Ganoderma species; lingzhi is another widely used name. This medicinal mushroom is tough and bitter rather than a usual culinary mushroom. Commercial reishi products may contain fruiting body, mycelium grown on grain, spores, mushroom powder, hot-water extract, alcohol extract or combinations.
Those forms are not interchangeable. Reishi mushrooms contain polysaccharides, including beta-glucans, and triterpenes such as ganoderic acids. Their amounts depend on species, growing substrate, plant part, extraction method and testing. A finding from one standardised reishi extract cannot automatically be applied to every mushroom supplement.
Traditional use can explain why people use reishi, but it does not establish modern efficacy. Laboratory activity also cannot show that swallowing a retail product will produce the same concentration, biological effect or health outcome in a person.
Benefits of reishi mushroom: what human studies show
The newest broad clinical review found very-low-certainty evidence across all outcomes. Modest pooled changes in body mass index, creatinine, heart rate and one oxidative-stress enzyme were reported, but the authors highlighted small trials, variation between studies and risk of bias. More familiar targets, including blood sugar levels, blood pressure, cholesterol, inflammation and liver enzymes, did not improve significantly overall.[1]
This distinction helps avoid three common errors:
- a chemical-assay result is not proof that a supplement reduces disease risk;
- a change in a laboratory marker is not necessarily a noticeable health benefit; and
- an association or subgroup result is not a dependable treatment effect.
The purported benefits may be biologically plausible, yet plausibility sits below replicated human trials. The studies also used very different preparations and dosing schedules, so there is no evidence-based universal dose.
Effects of reishi on immune system support
Beta-glucans can interact with immune signalling. A randomised trial of a specific beta-glucan derived from Ganoderma lucidum reported changes in T-lymphocytes, natural killer cells and immunoglobulin A in healthy adults after 84 days.[4] This is evidence of immune modulation, not proof that reishi can boost the immune system in a universally helpful way or reduce infections.
Immune activation is not automatically desirable. People taking immunosuppressants, including after a transplant or for autoimmune disease, need individual advice because a product promoted for immune function could work against their treatment plan. Product composition also matters: results from a purified beta-glucan do not validate whole reishi powder or a multi-ingredient blend.
Reishi and cancer research claims
Cell and animal research reports effects on cancer cell signalling, including breast cancer, lung cancer, prostate cancer and colorectal cancer models. These are research observations, not evidence that reishi supplements fight cancer in humans.
A Cochrane review found five small trials in people diagnosed with cancer. Study quality and reporting were generally poor, no trial recorded long-term survival, and reishi alone did not show the tumour response seen when it was studied alongside chemotherapy or radiotherapy. The reviewers found insufficient evidence to use Ganoderma lucidum as first-line cancer treatment.[2]
Cancer patients should not add reishi on the basis of immune markers or laboratory mechanisms. It may increase bleeding risk, interact with chemotherapy in theory, interfere with immunosuppressive treatment, and reishi spore powder may affect the CA72-4 tumour-marker result.[6] The oncology team needs the exact brand, ingredient list and dose, not just the word “mushroom”.
Blood sugar and heart health claims
A Cochrane review of cardiovascular risk factors did not find reliable evidence that reishi lowers blood pressure, blood glucose or cholesterol.[3] The larger 2025 analysis similarly found no significant overall effect on blood pressure, fasting blood sugar or lipid profile.[1] Reishi should therefore not replace diabetes, hypertension or cholesterol medicine.
Some sources call reishi an antioxidant or antiinflammatory agent. Much of that evidence comes from chemical assays, cultured cells or animal models. Even when a human biomarker changes, the clinical importance may be unclear. Anyone taking blood-pressure or glucose-lowering medicines should monitor under professional guidance rather than adding reishi to decrease blood sugar or lower blood pressure independently.
Safety of reishi mushroom use
Reported adverse effects include nausea, dry mouth, dizziness, constipation, itching and insomnia. Bleeding is a particular concern with anticoagulants or antiplatelet medicines. Stop before surgery only according to instructions from your surgeon or anaesthetist; do not change prescribed medicine yourself.
Rare liver injury has been reported, including a 2023 case after powdered reishi mushroom was taken with alcohol and older reports involving powder preparations.[5] Case reports cannot estimate how often this occurs or prove every product carries the same risk, but they justify caution. Stop taking reishi mushroom and seek prompt medical advice for yellow skin or eyes, dark urine, severe nausea or vomiting, unusual fatigue, loss of appetite, or upper abdominal pain.
Avoid reishi unless a clinician specifically supports its use if you:
- are pregnant or breastfeeding, because adequate safety data are lacking;
- have liver disease, a bleeding disorder or very low blood pressure;
- take warfarin or another anticoagulant, antiplatelet medicine, immunosuppressant or cancer therapy;
- have an operation or procedure planned; or
- developed an allergic or gastrointestinal reaction to a fungus or mushroom product.
Reishi dosage and product quality checks
Trials have used preparations ranging from purified constituents to powders and extracts, across widely different quantities and durations. This does not support a single dosing recommendation. “More concentrated” also does not mean more effective or safer.
If a clinician agrees that you can use reishi, record the brand and batch, follow the labelled directions, and avoid stacking multiple medicinal mushroom products. A useful label identifies the Ganoderma species, fruiting body or mycelium, extraction ratio or method, amount per serve, other ingredients, batch number and Australian sponsor. Independent contaminant testing is more informative than claims such as “full spectrum” or “high potency”.
An Australian therapeutic product should display an AUST L or AUST R number where applicable. That listing is not proof that every marketing claim has been independently proven. Food products and therapeutic goods also operate under different regulatory frameworks.
For broader context, read our evidence guide to medicinal mushrooms. This editorial link should go live only with the approved versions of both articles.
Reishi mushroom questions
What happens if you take reishi every day?
Daily use does not guarantee a benefit. Human trials used different products and durations, while long-term safety data remain limited. Side effects, bleeding interactions and rare suspected liver injury matter more than a promised timeline. Check with a clinician if you use medicine or have a health condition.
What is a reishi mushroom good for?
Reishi has a long history of traditional use and constituents with laboratory biological activity. Human evidence does not currently establish it as a treatment for cancer, diabetes, high blood pressure, high cholesterol or infection. A specific beta-glucan trial changed immune markers, but that did not prove fewer illnesses.
Is Lion’s Mane or Reishi better?
Neither is universally better. They are different fungi studied for different preparations and outcomes, and direct head-to-head clinical evidence is lacking. Choose based on a defined goal, safety profile and professional advice, not a broad “best mushroom” ranking. Do not assume results for lion’s mane, chaga or another mushroom apply to reishi.
What does reishi do to the liver?
The 2025 pooled trial analysis found no significant overall improvement in liver enzymes.[1] Laboratory and animal findings sometimes suggest protective mechanisms, but rare human liver-injury cases have also been reported.[5] Reishi is not a liver treatment. Stop it and seek care if liver-injury symptoms develop.
References
- Jafari A, et al. The nutritional significance of Ganoderma lucidum on human health: a GRADE-assessed systematic review and meta-analysis of clinical trials. Food Science & Nutrition. 2025;13(6):e70423. doi:10.1002/fsn3.70423. PubMed
- Jin X, et al. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database of Systematic Reviews. 2016;(4):CD007731. doi:10.1002/14651858.CD007731.pub3. PubMed
- Klupp NL, et al. Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors. Cochrane Database of Systematic Reviews. 2015;(2):CD007259. doi:10.1002/14651858.CD007259.pub2. PubMed
- Chiu HF, et al. Evaluation of immune modulation by beta-1,3;1,6-D-glucan derived from Ganoderma lucidum in healthy adult volunteers: a randomised controlled trial. Journal of Functional Morphology and Kinesiology. 2023;8(1):21. doi:10.3390/jfmk8010021. PubMed
- Guedikian R, et al. Ganoderma lingzhi (Reishi mushroom)-induced acute liver injury in the setting of alcohol use: a case report and review. Cureus. 2023;15(9):e45953. doi:10.7759/cureus.45953. PubMed
- Memorial Sloan Kettering Cancer Center. Reishi mushroom: clinical summary, adverse reactions and interactions. Updated 2026. Clinical monograph
Author bio
Prepared for Nutrition Market under Charles Gumbley’s practitioner-led editorial system. Nutrition Market sells supplements; this article contains no product, category, price, stock or purchase links.
Evidence checked: 19 July 2026. This general information is not a diagnosis or a substitute for medical, oncology or pharmacy advice.
