Reishi and the Immune System: Claims Checked
Reishi is marketed for immune support and cancer. This page checks what trials measured, what they did not, and why higher test values are not the same as fewer infections.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
Cancer care first. Reishi supplements are not a treatment for cancer. The National Cancer Institute (NCI) states that the US FDA has not approved medicinal mushrooms as a treatment for cancer or any other medical condition. [1] A Cochrane review found insufficient evidence to justify reishi as a first-line cancer treatment. [2] Anyone in cancer care should tell the oncology team about every product, including reishi. See mushroom supplements for people with cancer.
Immune medicines and autoimmune conditions. MSK advises asking a healthcare provider if you take immunosuppressants, because reishi may not be safe for you. [3] See mushrooms, autoimmune conditions and transplants.
The claim as marketed
"Reishi supports or boosts the immune system." MSK notes that reishi is used in many Asian countries to boost the immune system. [3] That describes how it is used. It is not a finding that it works. "Boost" is also a vague word: the immune system is not a single dial, and a higher result on one blood test is not the same as being better protected.Traditional use (not proof)
Traditional use only. NCI describes Ganoderma as having a very long history in East Asia as a medicinal mushroom, and says contemporary Chinese physicians use it to support immune function in people having chemotherapy or radiation. [1] This is tradition and practice. The evidence below is judged separately. See traditional versus clinically supported uses.What research found
| Question | What the source found | Strength of evidence | Population, form and size |
|---|---|---|---|
| Immune cells in healthy adults | In an 84-day daily trial of a reishi beta-glucan, T-cell counts, natural killer cell counts and IgA were higher than placebo; kidney and liver markers did not change. [4] | Promising but limited; lab markers only | Healthy adults 18 to 55; beta-glucan derived from G. lucidum |
| Immune cells in older women | Reishi dry extract for 8 weeks changed T-cell function in older women, which the authors read as a mainly anti-inflammatory action. [5] | Biomarker only; unclear meaning | 39 older women who finished; dry extract |
| Short-term tolerance | A rise in one immune cell type (CD56) in 16 volunteers over 10 days did not reach statistical significance. [6] | Insufficient evidence | 16 healthy volunteers; extract |
| Immune markers in cancer | A Cochrane review of 5 trials found small rises in the percentage of CD3, CD4 and CD8 cells (about 2 to 4 percentage points). Study quality was generally unsatisfying. [2] | Biomarker only; insufficient evidence for clinical benefit | People with cancer; various products |
| Lung cancer, open-label | In one trial, an aqueous polysaccharide extract did not significantly change group-level immune measures after 12 weeks. [1] | No good evidence of benefit on those measures | Advanced lung cancer; polysaccharide extract |
| Spore powder after surgery | A study of 120 breast and lung cancer patients examined immune markers with and without reishi spore powder. [7] | Biomarker study; insufficient evidence for outcomes | Post-operative patients; spore powder |
| Fewer infections | Proper evidence not found for reishi specifically. We searched PubMed for Ganoderma, reishi or lingzhi with infection, cold or respiratory terms in trials. A broader review of fungal beta-glucans from several fungi (including G. lucidum) reported fewer cold and respiratory symptoms in some interventions but inconsistent cell-level findings. [8] | Insufficient evidence | Mixed sources, not reishi alone |
A 2024 systematic review pooling 17 trials of reishi reported that, overall, the certainty of evidence was very low across outcomes. [9] Read together, trials show that some blood markers move in some groups. Whether that means fewer illnesses is not shown.
Cancer research in context
A 2023 systematic review of medicinal mushrooms in cancer care concluded that the evidence is inconclusive for routine use. [10] A narrative review noted that adverse events were poorly reported in the trials it covered. [11] Lab and animal findings on reishi compounds exist, but they are a separate (preclinical) kind of evidence; see human versus animal and lab research.What a reader can do
Ask a clinician or pharmacist before using reishi if you have an immune condition, take immune medicines or are in cancer care. For broader context, see mushrooms and immune function and mushroom supplement claims checked.Frequently asked questions
Does reishi boost the immune system?
Some blood immune markers rose in some trials, but the studies were small and did not show fewer infections. Proper evidence not found for infection outcomes in reishi-only trials. [4][8]
Can reishi treat cancer?
No. A Cochrane review did not find enough evidence to justify first-line use, and the FDA has not approved medicinal mushrooms as a treatment for cancer. [2][1]
Is reishi safe with immunosuppressants?
MSK says to ask your healthcare provider because reishi may not be safe for you. [3]
Can reishi make autoimmune disease worse?
MSK and a 2025 scoping review raise this as a concern for autoimmune skin disease, though cause is not established. [3][12]
Is reishi spore powder different?
Spore powder is its own product. MSK says it may raise a tumor marker (CA72-4) that can show on test results. [3] See reishi species, spores and fruiting body products.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety points specific to the immune claim
- Autoimmune skin disease: MSK says reishi may trigger or exacerbate autoimmune skin disease, though cause is not established. [3] A 2025 scoping review listed reishi among 15 herbal supplements with the strongest evidence of immune-stimulating effects, as a possible concern for people with autoimmune skin disease. [12]
- Transplant and other immune medicines: MSK flags immunosuppressants. [3] Ask the transplant or prescribing team.
- Quality: the NCI summary notes that supplement ingredients can vary from lot to lot. [1] See how to read a mushroom supplement label.
References
- National Cancer Institute. Medicinal Mushrooms (PDQ), health professional version. Read 2026-10-23.
- Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database Syst Rev. 2016. PubMed 27045603. Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center. Reishi Mushroom (Information About Herbs, Botanicals and Other Products). Read 2026-10-23.
- Evaluation of Immune Modulation by β-1,3; 1,6 D-Glucan Derived from Ganoderma lucidum in Healthy Adult Volunteers, A Randomized Controlled Trial. Foods. 2023. PubMed 36766186. Read 2026-10-23.
- Ganoderma lucidum dry extract supplementation modulates T lymphocyte function in older women. Br J Nutr. 2024. PubMed 38800991. Read 2026-10-23.
- Safety and tolerability of Ganoderma lucidum in healthy subjects: a double-blind randomized placebo-controlled trial. Am J Chin Med. 2007. PubMed 17597499. Read 2026-10-23.
- Dynamic biomarkers indicate the immunological benefits provided by Ganoderma spore powder in post-operative breast and lung cancer patients. Clin Transl Oncol. 2021. PubMed 33405051. Read 2026-10-23.
- Effects of fungal beta-glucans on health - a systematic review of randomized controlled trials. Food Funct. 2021. PubMed 33876798. Read 2026-10-23.
- The Nutritional Significance of Ganoderma lucidum on Human Health: A GRADE-Assessed Systematic Review and Meta-Analysis of Clinical Trials. Food Sci Nutr. 2025. PubMed 40510787. Read 2026-10-23.
- Medicinal Mushroom Supplements in Cancer: A Systematic Review of Clinical Studies. Curr Oncol Rep. 2023. PubMed 36995535. Read 2026-10-23.
- Significance of Medicinal Mushrooms in Integrative Oncology: A Narrative Review. Front Pharmacol. 2020. PubMed 33424591. Read 2026-10-23.
- Identifying immunostimulatory herbal supplements that may flare autoimmune skin diseases: a systematic scoping review. Lupus Sci Med. 2025. PubMed 41475897. Read 2026-10-23.