Medicinal mushrooms are often presented as powerful natural remedies, but the evidence remains mixed. Tradition and marketing often outpace clinical data. The best‑supported so far are beta‑glucans (RCTs suggest milder/shorter respiratory infections and sometimes improved allergy symptoms), while many other claims are mainly based on preclinical or smaller studies.
-
Effect and safety depend greatly on the product.The same mushroom can have different compositions depending on cultivation and processing (powder vs extract), and it is necessary to monitor quality/standardisation as well as contamination risk (mushrooms can accumulate heavy metals).
Medicinal mushroomsare attractive to many people mainly because they are attributed with a wide range of effects – from immune support and anti‑inflammatory properties to metabolic or cardiovascular links.
At the same time, it is fair to say that marketing and tradition often outpace the quality of evidence in humans. To date, only a few phase III studies have been conducted, and many studies involve relatively small numbers of participants – so even though the data are often “promising” (especially for immunity), the therapeutic value for specific diagnoses is still being clarified.
What are medicinal mushrooms?
Mushrooms form a separate kingdom of organisms, and there are millions of species worldwide; only a small portion are edible and an even smaller portion are described as “medicinal”. It is estimated that about 150,000 species exist, roughly 2,000 are considered edible, and over 200 species of wild mushrooms are listed as medicinal.
Medicinal mushrooms are generally those that are not only consumed as regular food, but also for their content of bioactive compounds – that is, substances that can influence certain processes in the body (e.g., immune response, inflammatory processes, etc.). In one review, the authors state that the therapeutic properties of mushrooms are not fully understood and that longer‑term clinical studies are needed to confirm effects, safety and dosing.
What bioactive compounds do medicinal mushrooms contain?
In medicinal mushrooms, it is most often mentioned that they contain substances such as beta‑glucans, triterpenes, phenolic compounds (polyphenols) and sterols. These groups of compounds are the main reason why mushrooms are studied for potential health effects.
Each mushroom species then contains different bioactive compounds in various proportions, forming a mixture, which is why different products (powder vs extract) can have different effects.
Beta‑glucans: fibre with potential immune effects
Mushroom beta‑glucans are components of mushroom cell walls and behave in a similar way to fibre. They are not digested in the upper digestive tract and may exert effects via both the gut and the immune system. Among the compounds found in mushrooms, beta‑glucans are some of the most consistently supported by research.
In a systematic review of 34 randomised controlled trials (RCTs), beta‑glucans from various sources (such as oyster mushroom, shiitake and reishi) were most commonly associated with immunomodulatory effects. In practical terms, this often meant fewer or milder symptoms of respiratory infections, and in some cases, improvements in allergy symptoms.
Other compounds include:
-
Polyphenols:A group of naturally occurring compounds found in plants and mushrooms, characterised by multiple phenolic structures. They are often linked to antioxidant activity and, in laboratory settings, can help neutralise reactive molecules (free radicals).
-
Triterpenes (triterpenoids): Lipophilic (fat‑soluble) compounds produced by mushrooms as secondary metabolites. In preclinical studies, they are frequently associated with anti‑inflammatory effects, for example, through influencing the production of certain inflammatory mediators.
-
Sterols:Molecules structurally similar to cholesterol that form part of cell membranes. In mushrooms, ergosterol is the most common sterol; it can be converted into vitamin D2 following exposure to UV light. Some sterols also demonstrate biological activity, primarily in laboratory models.
For many mushrooms, it is shown that they function as multicomponent mixtures. Their effects may result from the interaction of several compounds, and it is not always clear which is the primary active component. In the case of shiitake, for example, it has been observed that whole preparations (such as extracts, powders or mushrooms consumed as food) often exhibit a broader range of effects than isolated compounds. However, this also makes it more difficult to attribute specific effects to individual components.
Why a mushroom may work sometimes and not others
Each mushroom product/supplement can actually be something different
Even if the same mushroom name appears on the packaging, the content of active compounds can vary depending on the exact species used, how and where it was grown, the stage at which it was harvested, and which part of the mushroom was processed. All of these factors influence its composition.
There is also a significant difference between consuming mushrooms as food, using a powder (ground mushrooms) or taking an extract.
For food supplements, quality and dose matter
When it comes to supplements, quality and standardisation can vary considerably. In other words, products may not always contain what they claim, and the levels of active compounds may not be consistent. For shiitake, for example, it has been noted that even the measurement of glucanscanvary depending on the analytical method used, making it difficult to compare both studies and commercial products.
Dosage and duration of use also play an important role, as does the individual taking the supplement. Healthy young adults, older individuals, and those with specific health conditions may all respond differently.
Shiitake
Shiitake is an edible mushroom that has traditionally been used for immune support (particularly resistance to infections), as a “strengthening” supplement during cancer treatment (primarily in the form of isolated extracts rather than whole mushrooms), and occasionally in relation to cholesterol and cardiometabolic health.
Main active ingredients
In shiitake, the most commonly discussed compounds are beta‑glucans, particularly lentinan (a type of polysaccharide), which has been studied for its immunomodulatory effects. Other components include mixtures or complexes derived from the mycelium (such as various standardised extracts), as well as additional compounds like eritadenine, which is mainly studied in relation to lipid metabolism in preclinical models.
What studies in humans show
In one randomised dietary intervention, healthy adults consumed 5g or 10g of dried shiitake daily for four weeks. The study reported increased “reactivity” of certain immune cells, improved mucosal immunity (indicated by higher levels of secretory IgA in saliva) and a reduction in C‑reactive protein (CRP), a marker of inflammation. However, the absence of a placebo group limits the strength of these findings.
Another higher‑quality study, which was double‑blind and placebo‑controlled, examined a shiitake mycelium supplement in healthy older adults. The results were modest: while some changes were observed in certain white blood cells, most immune markers showed no significant difference compared with the placebo.
In another study, participants were given a mixture containing beta‑glucans derived from shiitake for eight weeks. This study found no clear benefit for immune or inflammatory markers compared with placebo, although some changes in gut microbiota were observed.
Possible risks
When consuming raw or insufficiently cooked mushrooms, so‑called “shiitake dermatitis” (itchy rash) may occur, as well as other issues (itching, fever, diarrhoea, mucosal lesions).
Lion’s Mane
Lion’s mane is an edible mushroom used as food in Japan and China. In traditional contexts, it is often attributed with “brain support,” memory and prevention of cognitive decline.
Main active ingredients
In lion’s mane, compounds such as hericenones (found in the fruiting body) and erinacines (found in the mycelium) have been identified. In laboratory studies, these compounds have been shown to support the production of nerve growth factor (NGF) in cultured cells.
Memory and thinking (cognitive function)
The most well‑known study was double‑blind and placebo‑controlled. It involved 30 individuals aged 50–80 with mild cognitive impairment. Over a period of 16 weeks, participants received either Lion’s Mane or a placebo. Cognitive test scores in the treatment group improved at weeks 8, 12 and 16. However, four weeks after stopping supplementation, scores declined again, suggesting that any effect may be temporary and dependent on continued use.
In contrast, results in younger, healthy individuals have been less convincing. In one placebo‑controlled study, university students consumed 10g of Lion’s Mane daily for four weeks, with no clear improvement in cognitive performance compared with placebo. This suggests that any potential benefits may be population‑dependent, potentially more relevant for older adults with cognitive concerns than for young, healthy individuals.
Reishi
Reishiis often used as a “vitality” mushroom. It is commonly taken for immune support, to help manage fatigue and stress, and sometimes in relation to inflammation or overall resilience.
Main active ingredients
Triterpenes (or triterpenoids) are considered among the primary biologically active compounds in reishi. These are produced in relatively high amounts in Ganoderma lucidum, the species most commonly referred to as reishi.
Blood sugar and metabolic syndrome
The largest and most methodologically robuststudy was double‑blind and placebo‑controlled in people with type 2 diabetes and metabolic syndrome, administering 3g of reishi daily (some had reishi alone, some reishi + cordyceps) for 16 weeks. No improvement was shown in the main sugar markers (HbA1c – average blood sugar over recent weeks and fasting glucose), nor in other risk factors (e.g., blood pressure, blood lipids).
Fatigue and “exhaustion” (neurasthenia)
In another study, 132 patients diagnosed with neurasthenia (broadly characterised by long‑term fatigue, exhaustion, and related symptoms) received either a reishi extract (Ganopoly) or a placebo for eight weeks, at a dose of 1,800mg three times daily. The group taking reishi reported greater improvements in fatigue ratings and overall clinical status compared with the placebo group. These outcomes were based on questionnaire and clinical assessment scales. According to the authors, the preparation was well tolerated. However, it is important to note that this study focused on a specific extract, and the findings relate primarily to subjective symptoms rather than objective (“hard”) health outcomes.
Immunity
There is also a studyinvolving healthy adults, in which participants took 200 mg of beta‑glucan derived from reishi daily for 84 days, compared with a placebo. The study reported increases in certain immune cells, higher levels of IgA and changes in natural killer (NK) cell activity. In terms of safety, liver and kidney function markers did not worsen, and the supplement was considered well‑tolerated. However, these findings are based largely on laboratory markers. The study does not demonstrate whether participants were actually less likely to become ill.
Cordyceps
Cordycepsis frequently marketed as a mushroom for energy, “vitality”, and physical performance. It is commonly used in relation to fatigue, endurance, and sometimes for immune support and recovery.
Main active ingredients
One of the most well‑known compounds in cordyceps is cordycepin, which is chemically similar to adenosine. Due to this similarity, it maypotentiallyinterfere with processes involving nucleic acids (RNA and DNA).
Physical performance and fatigue
In one double‑blind, placebo‑controlled studyinvolving older adults, the use of a fermented cordyceps product (typically referred to as Cs‑4) over 12 weeks led to improvements in certain exercise thresholds. However, it did not increase VO₂max, suggesting a modest improvement in exercise tolerance rather than a significant enhancement in overall fitness.
At the same time, there are also studies, particularly those involving athletes or short‑term supplementation, that have shown no clear improvement, especially in trained individuals. Overall, the evidence for performance benefits is mixed. Some improvements are occasionally observed in older or less‑trained populations, but these effects have not been consistently demonstrated in high‑performance athletes.
Immunity (mainly laboratory markers)
One of the most usable studies in healthy people monitored NK cell activity (cells that are part of innate immunity). After 8 weeks of using a mycelial extract (specific product), the cordyceps group had higher NK cell activity than the placebo. These are laboratory markers – the study does not directly prove that people actually had fewer infections.
Contamination risk – why origin and quality matter
When it comes to medicinal mushrooms, it is important to consider not only what they contain but also what they may have absorbed from their environment. Mushrooms are known to accumulate heavy metals such as cadmium, lead and mercury, meaning that those grown in contaminated areas may pose a risk.
For this reason, it is essential to check the origin of the raw materials, as well as the cultivation and processing conditions. This is important not only for safety, but also to ensure a more consistent level of bioactive compounds in the final product.
What are people’s experiences?
1) Better sleep and a calming effect (mainly reishi)
Common reports include “I’m calmer” or “I fall asleep better.” In addition, vivid dreams are repeatedly mentioned (some love them, others dislike them). Reddit
2) “Energy and performance” (mainly cordyceps)
People often describe subjectively “better energy,” better endurance or better workouts – though they sometimes admit that training volume or other lifestyle changes also played a role. Reddit
3) “Brain” – focus/mental clarity/mood (mainly lion’s mane)
Positive experiences most often revolve around a “clear head,” better focus or mood. Reddit
4) “Less sick/better immunity” (often turkey tail, reishi, blends)
Many users take it for immune support and praise that they get colds less often – typically without objective measurement, purely based on feeling and season. Nexus forum
There are also negative experiences
Anxiety/panic/depression (most discussed with lion’s mane)
On Reddit, there is a clear divide. While some users report benefits, others describe experiencing anxiety, panic attacks or low mood after taking Lion’s Mane.
Skin reactions (shiitake)
With shiitake, there are reports of rash/dermatitis (in discussions, it is often mentioned that this is related to insufficient cooking). Reddit
What to take away from this?
Medicinal mushrooms are not a miracle cure, but rather foods and supplements with some promising areas of research. The most consistent evidence to date relates to mushroom beta‑glucans, where clinical studies suggest potential benefits for immune function (such as milder respiratory infections or improvements in allergy symptoms). For many other claims, such as antioxidant effects, anti‑inflammatory properties, or performance enhancement, the evidence is largely based on laboratory or animal studies, with more limited and less conclusive findings in humans.
FAQs
Are medicinal mushrooms safe?
In most cases, when using high‑quality products and typical doses, medicinal mushrooms are generally well tolerated in healthy adults. For example, a systematic review of randomised controlled trials on mushroom beta‑glucans reported no adverse effects directly attributed to their use.
However, this does not mean they are entirely risk‑free. Mushrooms are complex, multicomponent substances, and individual responses may vary. Factors such as the form (whole mushroom versus concentrated extract), dosage, and interactions with medications all need to be considered.
Are medicinal mushrooms suitable for children?
For children, greater caution is needed because for many medicinal mushrooms (and especially their extracts), there is not as much quality clinical data on safety and dosing as there is for adults.
