Reishi: The Millennial Mushroom of Immortality
Used for over 2,000 years in traditional Chinese and Japanese medicine, Reishi (Ganoderma lucidum) is now gaining increasing interest in the West. Immunity, stress, antioxidant, sleep... Discover its real properties, documented benefits, and contraindications.
"Lingzhi" — a treasure of Eastern medicine now validated by modern science
Reishi, called Lingzhi in Chinese ("spiritual plant"), was once so rare that it was reserved for emperors and elites. Today, cultivated on a large scale, it has become one of the most studied medicinal mushrooms in the world, with over 400 clinical and preclinical studies documented in scientific literature.
In this article, we explore its unique composition, its adaptogenic, immunomodulatory, and antioxidant properties, its practical uses — and especially the precautions to be aware of before incorporating it into your routine.
What is Reishi?
Reishi (Ganoderma lucidum) is a mushroom with a woody consistency and a characteristic semi-circular shape, which grows naturally on the trunks and roots of deciduous trees — oaks, maples, elms — in temperate and subtropical areas of East Asia. Its shiny reddish-brown surface with lacquered reflections has earned it the nickname "lacquer mushroom."
In Traditional Chinese Medicine (TCM), Reishi is classified among the superior Qi tonics — substances that harmonize body and mind, strengthen vitality, and promote longevity. Ancient texts attribute to it the ability to "calm the spirit, strengthen the heart, and prolong life."
Wild Reishi is extremely rare — there was once 1 specimen for every 10,000 trees, which explained its precious nature. Today, almost all commercialized Reishi is cultivated on controlled substrates (sawdust, cereal grains). Quality varies considerably depending on the species used, the part of the mushroom (cap, stem, mycelium), the fruiting body/mycelium ratio, and extraction methods. For optimal effectiveness, prefer products from the whole fruiting body with a polysaccharide content of ≥ 30%.
Its unique phytochemical composition
The therapeutic richness of Reishi is explained by its exceptionally complex phytochemical composition. Here are the most active molecular families.
The beta-1,3/1,6-glucans of Reishi are the most well-documented molecules for immunomodulation. They bind to the surface receptors of immune cells — notably the Dectin-1 receptors of macrophages and dendritic cells — and activate a cascade of innate and adaptive immune responses. Unlike aggressive immunostimulants, Reishi's beta-glucans have a modulatory effect: they strengthen the response when it is weak and regulate it when it is excessive, which explains their relevance in contexts of immunodeficiency and autoimmune tendencies.
The 3 main properties of Reishi
This is the most documented property. Reishi polysaccharides regulate the activity of the immune system in both directions — stimulation in cases of immune weakness, regulation in cases of hyperactivity. This dual action distinguishes it from simple immunostimulants and makes it a particularly interesting ally in cases of recurrent fatigue, seasonal changes, or prolonged stress.
Reishi is one of the rare mushrooms classified as an adaptogen — meaning it can help the body better resist various forms of stress (physical, emotional, environmental) without excessive stimulating or sedative effects. Ganoderic acids notably act on the GABAergic system, explaining the observed effects on sleep quality and mild anxiety.
Reishi contains an exceptional concentration of polyphenols, triterpenes, and antioxidant polysaccharides that neutralize free radicals and protect cells from oxidative stress. These effects are particularly marked at the hepatic level — the liver being the organ most exposed to toxins — which explains the traditional use of Reishi as a hepatic tonic. Preclinical studies document a reduction in markers of liver damage in case of exposure to toxins.
What science says: recent studies
Here is an overview of the most recent clinical research on Reishi, in the three most well-documented areas.
Several randomized studies document an increase in the activity of Natural Killer (NK) cells and T lymphocytes in subjects supplemented with standardized Reishi extract. A meta-analysis published in PLOS ONE (2016) concludes moderate evidence of favorable immunomodulation, particularly in cases of immunosuppression or chronic stress.
A randomized clinical study from 2012 (Pharmacology, Biochemistry and Behavior) showed that ganoderic acids increase total sleep time and improve deep sleep quality via interaction with GABA-A receptors. A significant reduction in self-reported anxiety scores was observed after 4 weeks of daily intake.
Shimizu et al. (2006, Journal of Ethnopharmacology) identified that Reishi's ganoderic acids inhibit 5α-reductase, an enzyme involved in the conversion of testosterone to DHT — the main mediator of androgenetic alopecia. More recent work (Wang et al., Phytotherapy Research, 2024) confirms an improvement in the viability of dermal papilla cells in vitro.
Despite the richness of the literature on Reishi, the majority of studies are preclinical (in vitro or on animal models) or have limited clinical participant numbers. Large-scale randomized controlled trials in humans are still lacking for certain indications. The EMA (European Medicines Agency) classifies Reishi as well-established traditional use for immune support and comfort in cases of fatigue. It remains a natural supplement to be integrated into a healthy lifestyle, not a medication.
How and in what form to consume Reishi
Reishi is available in many galenic forms. The choice depends on your objectives, lifestyle, and the desired concentration of active ingredients.
The most practical and well-dosed form. Prefer double extraction extracts (water + alcohol) to concentrate both polysaccharides and triterpenes. Ideal content: ≥ 30% polysaccharides, ≥ 10% beta-glucans.
Versatile — can be incorporated into smoothies, broths, lattes, or culinary preparations. Strong bitter taste. Less concentrated than extracts; check the concentration ratio.
Traditional form. Dried slices simmered for 1 to 2 hours in water. Bitter and earthy flavor. Water extraction releases polysaccharides but not triterpenes (alcohol-soluble).
Rapid absorption, convenient to dilute in a drink. Hydro-alcoholic tinctures offer the most complete spectrum of active ingredients (polysaccharides + triterpenes).
Doses studied in clinical trials vary between 1.5 g and 9 g of Reishi powder per day, or equivalent in concentrated extract (generally 500 mg to 1.5 g of 10:1 extract). A course of 6 to 12 weeks is generally necessary to observe significant effects on immunity and stress. It is recommended to take breaks (e.g., 8 weeks of intake, 2 weeks off) and to start with the minimum dose to assess individual tolerance.
Contraindications and precautions for use
Reishi is generally well tolerated at physiological doses, but several situations require particular vigilance or prior medical consultation.
Reishi is not recommended during pregnancy and breastfeeding due to the lack of safety studies in these situations. As a precaution, its use should be avoided or strictly validated by a doctor or midwife.
Reishi has mild anticoagulant and antiplatelet properties. In combination with medications such as warfarin, aspirin, or clopidogrel, it can potentiate the anticoagulant effect and increase the risk of bleeding. Medical consultation is imperative before taking it.
Due to its anticoagulant effect, it is recommended to stop reishi at least 2 weeks before scheduled surgery to avoid any risk of increased bleeding. Always inform your surgeon and anesthetist about any supplements you are taking.
Although reishi is immunomodulatory and not simply immunostimulatory, people suffering from autoimmune diseases (lupus, multiple sclerosis, rheumatoid arthritis) or undergoing immunosuppressant treatment should consult their doctor before consuming it, as a precaution.
At high doses or with prolonged use (> 3 to 6 months without a break), reishi can cause: mild digestive discomfort, dry mouth, dizziness or, very rarely, reversible liver reactions. These effects are generally dose-dependent and disappear with reduction or cessation. Always start with the minimum recommended dose and gradually increase according to your tolerance.
FAQ — Frequently asked questions about reishi
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Gynecologist practicing in Paris for 18 years, specialized in women's hormonal health, perimenopause and menopause. At Nutremys LAB, she brings her medical perspective to every product we offer.
Learn more →The information shared on this blog is for educational and informational purposes only. It does not replace medical consultation, diagnosis or treatment prescribed by a healthcare professional. If you have symptoms, are undergoing treatment or are pregnant, consult your doctor before modifying your diet or starting supplementation. Nutremys LAB food supplements should not replace a varied, balanced diet or a healthy lifestyle.
