Reishi
Ganoderma lucidum
TL;DR
Reishi at 1.5-3 g/day of a hot-water extract standardised for beta-glucans is the most credible immune-modulating mushroom, with human trials showing shifts in NK-cell activity and lymphocyte populations. Sleep and stress claims rest largely on rodent work and traditional use, and Cochrane found no survival benefit as a cancer treatment.
Ideal For
- Adults wanting long-horizon immune modulation rather than acute cold treatment
- People under sustained stress looking for an adaptogen with an immune angle
- Those already tolerating other beta-glucan sources and wanting a broader mushroom base
- Patients seeking a quality-of-life adjunct during oncology care, with their team's approval
Avoid If
- You take anticoagulants or antiplatelet drugs — reishi has mild antiplatelet activity
- You are within two weeks of surgery
- You have had an organ transplant or take immunosuppressants
- You are pregnant or breastfeeding
- You have low blood pressure, since reishi may lower it further
- You are considering it as a replacement for cancer treatment
Frequently Asked Questions
Does reishi treat cancer?
Will it make me sleepy?
Fruiting body or mycelium?
How long before anything happens?
Overview
Ganoderma lucidum has been used in Chinese medicine for two thousand years and is now one of the most heavily marketed functional mushrooms. The active fraction is not the fruiting-body biomass sold in cheap powders but the polysaccharides — chiefly beta-1,3/1,6-glucans — extracted by hot water, plus a set of lipid-soluble triterpenes (ganoderic acids) that require an alcohol extraction step. Products that list "mushroom powder" without an extract ratio or beta-glucan percentage are largely mycelium grown on grain, and the grain shows up as starch on analysis.
The strongest human data is immunological. Trials in cancer patients receiving Ganoderma polysaccharide alongside chemotherapy report increased NK-cell cytotoxicity and CD3/CD4 counts, and a Cochrane review concluded the evidence supports use as an adjunct for immune parameters and quality of life while explicitly rejecting it as a primary treatment. That distinction matters and is frequently blurred in marketing.
The calming reputation is more traditional than trialled. Rodent studies show reduced sleep latency and increased non-REM sleep, plausibly through adenosine pathways, but the human sleep literature is thin. Where reishi earns its place in a stack is as a slow, cumulative immune and stress-buffering agent taken over months, not as an acute sedative.
How It Works
- Beta-1,3/1,6-glucans engage dectin-1 and TLR2/4 receptors on innate immune cells
- Increases NK-cell cytotoxicity and CD3/CD4 lymphocyte counts in clinical trials
- Ganoderic acid triterpenes inhibit histamine release and 5-alpha-reductase activity
- Modulates HPA-axis output, reducing corticosterone responses in animal stress models
- Enhances non-REM sleep in rodents, likely via adenosinergic signalling
- Provides hepatoprotective antioxidant activity through increased SOD and glutathione
Quick Facts
- Potent immune modulator
- Reduces stress and anxiety
- Supports deep sleep
- Anti-inflammatory effects
- Longevity promoting
Benefits & Outcomes
Tumor Response Rate
Reishi is used adjunctively in some settings with weak and low-quality evidence.
Stress Resilience
Reishi extract at 1.5-3 g/day reduced subjective fatigue and improved wellbeing over eight weeks in controlled work, supporting a slow adaptogenic effect.
Improved Sleep Quality
Reishi's sleep reputation rests mainly on rodent sleep-architecture work and traditional use; human trials report improved wellbeing but rarely measure sleep directly.
Health Concerns Addressed
No linked health concerns yet.
Supporting Research3 studies
Ganoderma lucidum (Reishi mushroom) for cancer treatment
Jin X, Ruiz Beguerie J, Sze DM +1 more
Patients receiving Ganoderma lucidum alongside conventional treatment were more likely to show a tumour response and had increases in immune cell measures and some quality-of-life scores. No survival benefit was demonstrated, and the included trials were few, small and at moderate to high risk of bias.
A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia
Tang W, Gao Y, Chen G +6 more
After 8 weeks, the reishi group showed significantly greater reductions in Clinical Global Impression severity scores and fatigue ratings, and greater improvement in sense of well-being, than placebo. The extract was well tolerated with no serious adverse events.
A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia
Tang W, Gao Y, Chen G +1 more
Ganoderma polysaccharide extract significantly reduced fatigue and Clinical Global Impression severity over eight weeks.
Safety Information
Potential Side Effects
Very safe. May cause digestive upset, dry mouth, or dizziness in some. Can have mild blood-thinning effects. Typical dose 1000-3000mg dried mushroom or 500-1500mg extract daily. Take evening for sleep support. Safe for long-term use.
Contraindications
Bleeding disorders, low blood pressure, surgery (stop 2 weeks before)
Drug Interactions
- Blood thinners
- Immunosuppressants
- Blood pressure medications
Pregnancy & Breastfeeding
Pregnancy: Likely unsafe
Breastfeeding: Not enough evidence to judge
Dosage Guidelines
Dosage Used in Studies
1000-5000 mg
Best Time to Take
Evening or before bed
Best Form
Dual extract (water and alcohol)
Bioavailability
Contains polysaccharides (water-soluble) and triterpenes (alcohol-soluble). Dual extraction captures both. Adaptogenic and immune-modulating effects. May take 4-8 weeks for full benefits.
Dosing by Goal
| Goal | Dose | Notes |
|---|---|---|
| Standard | 1.5-3 g/day of hot-water extract, equivalent to roughly 9-18 g dried fruiting body | |
| Immune adjunct | Up to 5.4 g/day of polysaccharide extract in oncology trial protocols, under supervision | |
| Beta-glucan target | Aim for at least 20-25% beta-glucan on the certificate of analysis | |
| Timing | Split morning and early evening; not acutely sedating despite the reputation | |
| Duration | Immune parameter changes appear over 8-12 weeks, not days |
Forms Compared
Hot-water fruiting-body extract
The evidence-backed form; look for 8:1 or higher ratio and stated beta-glucan percentage
Dual-extract (water plus alcohol)
Captures both polysaccharides and triterpenes; the most complete preparation
Spore oil / cracked spores
Triterpene-rich and expensive; less trial data than polysaccharide extracts
Mycelium on grain
Cheap and common; high starch, low beta-glucan, largely not what was studied
Reishi coffee or blends
Doses are typically far below the 1.5 g extract threshold
Food & Timing
With or without food; splitting the dose improves tolerability
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.