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Mushrooms & fungal extracts

Reishi

Reishi / lingzhi Ganoderma mushroom products

Reishi (lingzhi) describes mushroom powders, extracts, and spore products that are not interchangeable. Human evidence does not establish a strong cognitive or sleep benefit. Compare fungal part, extraction method, stated markers, dose context, and safety documentation before comparing listed prices.

Standardized ExtractFull Spectrum ExtractWater ExtractAlcohol ExtractDual ExtractLimited Human EvidenceMixed Evidence
Updated August 2026/6 min read/9 citations
Reviewed by the NootropicsIndex editorial team.Method: prioritize cited human research and official safety or regulatory sources; compare retailer-listed prices without endorsing products.Affiliate disclosure
01

What is it?

Limited evidence for cognitive use8
Reishi has a long traditional-use history, but human research does not establish a reliable cognitive or sleep benefit. A useful comparison starts with the exact product form and its safety documentation.

What reishi describes

1

Reishi and lingzhi labels can describe different Ganoderma mushroom products. Retail listings may be fruiting-body powder, mycelium biomass, spores, or an extract; those forms should not be considered interchangeable.

Human evidence is narrow

2

An 8-week randomized trial studied a specific Ganoderma polysaccharide extract in Chinese patients with A nervous-exhaustion term used for physical and mental fatigue.Source. That population and preparation do not establish broad focus, memory, or sleep benefits for healthy users.

Sleep claims remain unconfirmed in humans

4

Sleep-related findings cited for reishi are often preclinical. They should not be presented as evidence of a predictable human sleep effect.

Practical buying takeaway8
Reishi is a better fit for form-aware mushroom research than for promised nootropic or sleep effects. The page should help compare product composition, evidence limitations, and safety context without endorsing a seller or claim.
02

Names, aliases and forms

Common NameReishi
Latin NameGanoderma lucidum
Traditional NameLingzhi
Fungal PartsFruiting body; Spores
Active ConstituentsBeta-glucans; Triterpenes
03

Potential effects and evidence map

Human studies are heterogeneous and do not establish a reliable cognitive or sleep benefit; the 2025 clinical-trial meta-analysis rated certainty very low across outcomes.

Effect domainMagnitudeGrade
Stress resilience2
CumulativeConfidence: Low

May have limited fatigue/calm relevance in narrow symptom contexts, but this should not be generalized to healthy-user stress resilience.

Note The main human trial used a polysaccharide extract in neurasthenia, not a general nootropic population.

1/5
C
Sleep quality4
UnknownConfidence: Low

Sleep-support claims are not well validated in humans.

Note A sleep mechanism paper is animal/preclinical and should not be upgraded to human sleep efficacy.

1/5
D
Calm / relaxation2
UnknownConfidence: Low

Calm or relaxation claims remain mostly traditional or indirect.

Note Use calm-language cautiously unless a product has matching clinical evidence.

1/5
D
Memory / learning6
UnknownConfidence: Medium

Direct memory, learning, or focus benefits are not established.

Note Reishi should not be positioned as a primary cognitive-enhancement mushroom.

0/5
E
04

Typical dosages and timing

Typical
500-3000 mg/day
Not a recommendation
Lower bound
500 mg/day
Profile value
Upper bound
3000 mg/day
Profile value
Reported consumer range1500-3000 mg/day

Published consumer ranges are broad, and studies use very different preparations. Raw powders, spores, and concentrated extracts should not be compared by weight alone.

05

Timing & effect horizon

Effect horizonCumulative
Cumulative
Study window2Cumulative
8 weeks
What the timing evidence shows2

The featured 8-week fact is a study window for one polysaccharide extract in one patient population. It does not establish an acute onset, single-dose duration, or cycling schedule for retail reishi products.

06

Safety, side effects and risk profile

Rare liver signal warrants context1
Small short-term trials did not show liver-test changes, but rare reported liver injury has been attributed to reishi products. LiverTox notes that causality is uncertain in many reports and clinically apparent injury appears extremely rare.
GI discomfort5
Confidence: Low

Small studies report few adverse effects; everyday side-effect frequency across product types is uncertain.

Note Spore-product findings do not automatically apply to other reishi forms.

1/5
C
Evidence uncertainty8
Confidence: High

Evidence varies by study population, preparation, dose, and duration.

Note The 2025 meta-analysis rated certainty very low across outcomes.

2/5
C
Legal / regulatory risk7
Confidence: High

U.S. supplement marketing has claim and labeling limits; this is not a global legal conclusion.

Note FDA regulatory scope is jurisdiction-specific and date-sensitive.

1/5
B
Reported effects5Product-specific and uncertain

Small trials often reported few adverse effects. Reported digestive or other symptoms should be interpreted cautiously because commercial product composition and study reporting vary.

07

Interactions and cautions

Interaction evidence9

A small 4-week trial in healthy volunteers found no hemostasis impairment at 1.5 g/day. It does not establish safety with medicines, surgery, or higher-risk populations, so compatibility should not be assumed.

08

Legal and regulatory status

U.S. status7

In the United States, as of 2026, dietary supplements are not FDA-approved before marketing. Manufacturers remain responsible for lawful labeling and substantiation; disease-treatment claims are not appropriate for supplement products.

09

How it compares

Comparison lens8

For a price comparison, the relevant question is whether two products use comparable mushroom material and extraction. Do not assume a powder, spore product, and standardized extract are equivalent.

10

Practical buying and quality notes

  • Compare listed prices only after matching fungal part, extraction method, stated marker compounds, serving size, and whether the product is a single ingredient or blend.8
  • A useful label identifies the fungal part and extraction method. Product form is a more meaningful comparison than the word reishi alone.1
  • For extracts, check how constituents are described and whether a batch-specific certificate of analysis is available. Do not assume a generic polysaccharide percentage establishes beta-glucan or triterpene content.8
  • Use price per gram or serving only within a comparable product form. Include serving size, extract specification, and independently accessible batch documentation in the comparison.8
11

FAQ

What reishi dosage has been studied?

1

Reported dose ranges vary with the preparation. LiverTox lists a usual range of 500 mg to 3 g daily, while one 8-week polysaccharide-extract trial used 1,800 mg three times daily; that study regimen is not a general recommendation for retail products.

How long does reishi take to work?

8

There is no established acute onset or single-dose effect duration for retail reishi products. Human trials have used multi-week courses, but study length does not prove a predictable timeline or cycling schedule.

12

References

  1. NIH LiverTox. Lingzhi, Reishi. Updated October 5, 2024. NCBI Bookshelf.
  2. Tang W, Gao Y, Chen G, Gao H, Dai X, Ye J, Chan E, Huang M, Liu Z, Liu X, Zhou S. A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia. J Med Food. 2005.
  3. Klupp NL, Chang D, Hawke F, Kiat H, Cao H, Grant SJ, Bensoussan A. Ganoderma lucidum mushroom and cardiovascular risk factors. Cochrane Database Syst Rev. 2015.
  4. Yao C, Wang Z, Jiang H, Yan R, Huang Q, Wang X, et al. Ganoderma lucidum promotes sleep through a gut microbiota-dependent and serotonin-involved pathway in mice. Sci Rep. 2021.
  5. Thuy NHL, Tu VL, Thu LNA, Giang TT, Huyen DTK, et al. Pharmacological Activities and Safety of Ganoderma lucidum Spores: A Systematic Review. Cureus. 2023.
  6. Swallah MS, Bondzie-Quaye P, Wu Y, Acheampong A, Sossah FL, et al. Therapeutic potential and nutritional significance of Ganoderma lucidum - a comprehensive review from 2010 to 2022. Food Funct. 2023.
  7. U.S. FDA. Questions and Answers on Dietary Supplements.
  8. Jafari A, Mardani H, Mirzaei Fashtali Z, Arghavan B. The Nutritional Significance of Ganoderma lucidum on Human Health: A GRADE-Assessed Systematic Review and Meta-Analysis of Clinical Trials. Food Sci Nutr. 2025;13(6):e70423.
  9. Kwok Y, Ng KFJ, Li CCF, Lam CCK, Man RYK. A prospective, randomized, double-blind, placebo-controlled study of the platelet and global hemostatic effects of Ganoderma lucidum (Ling-Zhi) in healthy volunteers. Anesth Analg. 2005;101(2):423-426.
Note

This page is informational and summarizes available evidence. It is not medical advice, a recommendation, or a substitute for guidance from a qualified clinician.