Reishi (Ganoderma lucidum) — What the Research Actually Shows

Last updated: 25/08/2026

Here's every claim about Reishi, graded by how strong the actual evidence is. Links included where I have them.

A note on tradition

Reishi has been used in Chinese medicine for over 2,000 years — called Lingzhi, "spirit plant" or "mushroom of immortality." That's not scientific proof of anything. But that much sustained use without an established pattern of acute harm does suggest it's reasonably well-tolerated in its traditional form (mostly water decoctions), and a reputation that consistent, over that much time, may well point to real effects modern research just hasn't isolated or measured yet.

Athletic performance / recovery

Type: Human trials — Evidence: Strong A 2025 meta-analysis (14 RCTs, 528 athletes) found real, significant improvements in fatigue and recovery markers. One of Reishi's better-supported claims. [https://pmc.ncbi.nlm.nih.gov/articles/PMC12631420/]

Immune support

Type: Human trials — Evidence: Medium Multiple RCTs (randomized control trials) show real changes in immune cell activity, including in older women specifically. Hasn't been shown to actually reduce how often you get sick. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9914031/]

Cancer-related fatigue / quality of life

Type: Human trials — Evidence: Medium RCT (randomized control trial) with placebo control. Improved fatigue, mood, and inflammation markers in cancer patients during treatment. Different claim from "treats cancer" — this is about feeling better during treatment. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3236089/]

Cancer (alongside chemo/radiotherapy)

Type: Human trials — Evidence: Weak There was preliminary evidence that Reishi may have beneficial effects on immune markers and quality of life, and may enhance tumor response when added to chemotherapy/radiotherapy, but the underlying clinical evidence was too weak to establish these effects with confidence. [https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD007731.pub3/full]

Fatigue / neurasthenia (non-cancer)

Type: Human trial — Evidence: Medium A real 132-patient RCT found significantly better fatigue scores and wellbeing after 8 weeks vs. placebo. Solid single trial, not yet repeated elsewhere. [https://pubmed.ncbi.nlm.nih.gov/15857210/]

Blood sugar

Type: Human trial — Evidence: Medium (AGAINST) Reishi did not improve blood glucose or metabolic risk factors over 16 weeks. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4980683/]

Heart health, cholesterol, inflammation

Type: Human trials — Evidence: Weak The best pooled evidence (17 RCTs, 971 people) found no real effect on blood pressure, cholesterol, or glucose. A separate 2026 trial found no improvement in inflammatory markers either. [https://pmc.ncbi.nlm.nih.gov/articles/PMC12160064/]

Sleep

Type: Human trial — Evidence: Weak A large 2026 trial found Reishi beat melatonin for insomnia — but it's one study, brand new, and not yet peer-reviewed. [https://www.patientcareonline.com/view/reishi-mushroom-extract-outperformed-melatonin-for-chronic-insomnia-in-new-study]

Liver — protective effect

Type: Human trial — Evidence: Weak One placebo-controlled trial found a polysaccharide extract reduced hepatitis B viral markers in about 1 in 4 patients over 12 weeks. Real, but a single trial with a modest response rate.
https://www.researchgate.net/publication/269620103_A_Phase_III_Study_of_a_Ganoderma_lucidum_Curt_Fr_P_Karst_Ling_Zhi_Reishi_Mushroom_Extract_in_Patients_with_Chronic_Hepatitis_V

Allergies / asthma

Type: Human trial — Evidence: Weak A small randomized trial found that ASHMI, a three-herb formula containing Reishi, improved some measures of allergic asthma, but because Reishi was combined with two other herbs, the specific contribution of Reishi remains uncertain. https://pmc.ncbi.nlm.nih.gov/articles/PMC12160064/

Skin / anti-aging

Type: Lab study (human cells) — Evidence: Weak Reduced signs of cellular aging in skin cells in a dish. Not tested on actual skin or in people. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11854148/]

General longevity mechanism

Type: Lab/animal study — Evidence: Weak Extended lifespan in roundworms and triggered a cellular "cleanup" process (autophagy) in human cells in a dish. Interesting mechanism, nowhere near evidence of a human lifespan effect. https://pmc.ncbi.nlm.nih.gov/articles/PMC8202889/

"Adaptogen" label

Type: No real evidence — Evidence: Weak A small placebo-controlled trial found no significant effect of Reishi on cortisol or catecholamines, providing no support from this study for claims that Reishi acts as an adaptogen by modulating the human stress-hormone system. https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/study-of-potential-cardioprotective-effects-of-ganoderma-lucidum-lingzhi-results-of-a-controlled-human-intervention-trial/EA5C9B682C6C112A0D6D0396E06B96E3?utm_

Safety

Reishi has been used in traditional Asian medicine for more than 2,000 years and appears generally well tolerated in short-term human studies. However, long-term safety data remain limited, and Reishi may have antiplatelet effects that could increase bleeding risk when combined with anticoagulant or antiplatelet medications. Safety during pregnancy and breastfeeding has not been adequately established, so it is best avoided during these periods unless specifically recommended by a healthcare professional. If you take regular medication, have a bleeding disorder, are preparing for surgery, are pregnant/breastfeeding, or have another reason to be concerned about interactions, consult your doctor or pharmacist before using Reishi.

Evidence changes — I'll update this as new research comes out.