Bioavailability of medicinal mushroom supplements


When you buy a dietary supplement, you automatically assume that you will benefit from it. But this assumption is not always justified: quite a few supplements contain limited or no bioavailable bioactive ingredients at all. ('Bioavailable' meaning: the human body is able to digest and absorb the ingredient.)

The average consumer will not be aware of this limited bioavailability (this information is never revealed on the supplement's label) so is basically wasting his money. Examples of ingredients with limited or no bioavailability are e.g. resveratol, green tea extract (ECGC) and betulinic acid.

We want to discuss a whole group of supplements that are mostly useless unless they've been subjected to processing: medicinal mushroom supplements (sold in the form of capsules, powder, tablets, and aqueous solutions/tinctures). Medicinal mushrooms became very popular during the past 10 years, not in the least because of health gurus like David Wolfe, Cass Ingram and Daniel Vitalis. Examples of medicinal mushrooms are Reishi, Chaga, Cordyceps, Maitake and Coriolus, to name a few popular ones.

immunological effects of 39 mushroom products compared. The black bars - effects of the extracted products - white bars the effects of the non-extracted products. To cut straight to the conclusion: unless mushrooms (both raw and dried) have been subjected to an extraction process they are basically indigestible for the majority of people and you will not experience noteworthy therapeutic effects. The majority of mushroom products on the market have not been subjected to an extraction process. The bioavailability of the active ingredients is low at best (± 1/30th to 1/50th of a genuine extract) and the term 'extract' is often used in a deceiving way.

A 2015 study performed by Bastyr University offers additional proof. While investigating two specific immunological parameters the differences (therapeutic effect) between extracted and non-extracted mushroom products were very obvious.

Technical background

The reason for the limited bioavailability is this: mushroom cells are made of chitin, the same material that covers e.g. insects, lobsters and crabs. Chitin is the hardest all-natural material known to man. Locked in the chitin cell-walls of medicinal mushrooms are the bioactive and therapeutically interesting components. The keyword here is 'locked'.

Humans cannot digest chitin properly; the enzyme chitinase, needed to break down chitin, is not very active in our stomach acid; until recently it was considered to be absent, even. One small study has investigated the chitinase activity in a group of 25 young men. In brief, the outcome was that only 20% of the 25 test subjects were found to have good chitinase activity, and another 20% were found to have zero chitinase activity. 60% had poor chitinase activity. It is quite clear that if you want to be certain you'll get the therapeutic effects you're after you're not going to gamble - you choose an extract.

The therapeutic effects of non-extracted mushrooms are therefore unpredictable at best, not to say negligible. This is also the reason traditional medicine systems that include medicinal mushrooms in their repertoire (like Traditional Chinese Medicine), only use them in decoctions, teas or soups, never simply dried/powdered, in tinctures or raw. Scientific research, a cornerstone in the marketing of mushroom products, is always using extracts.

Extraction procedures

The most common and cheapest extraction technique is hot-water extraction: the hot water will 'melt' the chitin and release the water-soluble bioactive components. The highest yield of bioactive ingredients is achieved when a high temperature combined with high pressure (211-373 ºF and pressure up to 50 psi to prevent disintegration of the moleculal structure of the bioactive constituents) is used. As a second step hot ethanol extraction is used in more sophisticated mushroom products: this will release the non-water solubles as well; basically, all bioactives will become bioavailable when this step is also included. Do not confuse this with an alcohol tincture: simply adding mushroom powder to alcohol will not have a lot of effect. Unlike cellulose (herbal products) chitin does not degrade in alcohol.

Most consumers will have no knowledge of these technical details. You only have the supplement-facts label and a website/brochure filled with power-statements. In brief: you can trust the first one (by law it is prohibited to exaggerate or lie on that label) and the second one you can consider mainly marketing talk, which can have varying levels of truth.

The good thing is that the label will tell you everything you need to know.

Supplement facts label of Aloha Medicinals' Chaga GOLD: this is not an extract but just encapsulated powder

Only if the label gives you details like "40% polysaccharides" "10 mg ergosterol" "2% betulinic acid" you can be 100% sure you have a genuine extract. General statements like "contains a high level of beta-glucans", "over 200 phytonutrients!" "contains PSP/PSK" are only found on non-extracted products; genuine extracts will always state the exact numbers. Simply, because they can, plus it provides them with a USP (Unique Selling Point). Non-extracted mushroom products can never claim a guaranteed percentage of whatever active ingredient. Levels do vary between mushrooms even if they were harvested in the same area. This is the case with all natural products.

Extracts or no extracts ?

Finally, the use of the term 'extract' can be very deceiving. Genuine mushroom extracts are in general the result of solvent extraction (hot water, maybe also hot ethanol). The bioactives are freed, diluted and concentrated in the solvent and then isolated.

However, we came across several 'extracts' that used terms like "10:1 extract". This is misleading, because it basically refers to drying or concentrating a large amount/size to a smaller amount/size. It cannot be considered an indication of potency if there is no further specification of bioactives as described above. In this particular case we can state that e.g. 10:1 means it is simply a dried and powdered mushroom: mushrooms are often ± 90% water, so a completely dry mushroom has been reduced to 10% of its original weight. Herbal tinctures always use this indication of potency, but mushrooms are not herbs and do not disintegrate in alcohol or cold water, like dried herbs do.

oriveda chaga supplement facts label
mushroom science chaga supplement facts label
Supplement facts labels of Oriveda (top) and Mushroom science (bottom) products. Genuine extracts.

Supplement facts label of Planetary Herbals' Chaga Full Spectrum: this is not an extract but just encapsulated powder

Supplement facts label of Mushroom Wisdom's Maitake D-Fraction Pro 4X: many of their products are a combi of Maitake extract and dried powdered another mushroom; here it's Maitake. One tablet is ± 160mg - only 12 mg (the 30% proteoglucan contained in the 40 mg extract fraction) can be considered bioactive.

Certificates of Analysis

To get 100% certainty about the quality of the product you're about to buy, requesting a COA (Certificate of Analysis) is also an option, in particular when dealing with online sellers. Few sellers will share the original COA (issued by the producer) with you, though. Statements about proprietary information are a common way to avoid giving any verifiable details; in our opinion this can be considered a red flag. If they do not want to reveal their manufacturer, blocking the manufacturer's name on the COA would be sufficient, for instance. Instead, they prefer to keep all the facts (heavy metal contamination, levels of bioactives -or the lack thereof-, etc.) under the blanket. We might dedicate a future article to this subject.

An example of very deceiving marketing

One American producer, Aloha Medicinals, put the COA of all their products online to backup their claims about potency. In itself this is very good, but when we had a closer look it turned out that

  • almost all COAs were issued by Atlas Bioscience, recently unmasked as a 'dry lab', which makes us question their reliability
  • several of their COAs revealed that prior to analysis an enzyme treatment with chitinase took place, meaning the results of the analysis are no longer of the product being offered for sale, but of an extracted version of that product.
This is very deceiving, since most consumers will not know what this pretreatment implies and will assume they are buying a high-potency extract. Instead, they get mostly undigestible encapsulated mushroom powder. An example of such a COA can be found here.


We came to the conclusion that the majority of mushroom products sold are non-extracted, mostly indigestible products that will not result in any noteworthy therapeutic effects. Some sellers even try to pass 'non-extracted' off as a preferable thing ["Exposing (…) to high heat destroys many of the interesting metabolites. Our raw philosophy is that the synergistic effect of all raw nutrients is superior to the cooked, isolated effects of a few nutrients." - The Longevity Warehouse, on their website] An interesting philosophy, except you cannot digest a single one of those nutrients properly.

With the information in this article you now also know better. The supplement-facts label can help you to make the right choice.


- The Pharmacological Potential of Mushrooms

- Chitin

- Chitinase in gastric juices ?

- Chitin induces accumulation in tissue of innate immune cells associated with allergy

- Significant Correlation between TLR2 Agonist Activity and TNF-α Induction in J774.A1 Macrophage Cells by Different Medicinal Mushroom Products

- Hot compressed water extraction of polysaccharides from Ganoderma lucidum using a semibatch reactor