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The Truth Behind Polysaccharides in Medicinal Mushrooms

The Truth Behind Polysaccharides in Medicinal Mushrooms
Written by Skye Chilton - Updated: June 17, 2024

Why Polysaccharides are a Poor Measurement of Mushroom Quality

Polysaccharides are one of the key active components in medicinal mushrooms and they are commonly listed on many medicinal mushroom products. In fact, many companies boast about high polysaccharide numbers. However, if we look deeper it becomes clear that polysaccharide analysis may be hiding significant product flaws.

Are high polysaccharides really a measure of quality?

Actually polysaccharides include more than just compounds found in mushrooms which means many mushroom products are fooling you with their polysaccharide numbers.

But first...

What are Polysaccharides?

polysaccharides molecular structure

Polysaccharides are long chain carbohydrates that are made up of various monosaccharides connected by glycosidic bonds. These molecules can range from the very simple to the more complex carbohydrate molecules.

Some examples of polysaccharides would be chitin and beta-glucans, which make up the cell walls of fungi. Cellulose, which is what plant cell walls are made up of are also polysaccharides. Starch and glycogen are also polysaccharides.

Polysaccharides are considered to be one of the most commonly mentioned active compounds in plants and fungi. Specific types of mushrooms like reishi (Ganoderma lucidum), turkey tail (Trametes versicolor) and Maitake (Grifola frondosa) possess high levels of polysaccharides.

Polysaccharides in Fungi - Beta-glucans

beta-glucan molecular structure

Now that we’ve defined what polysaccharides are, we will look specifically at the polysaccharides you find in fungi. Fungi will contain small amounts of glycogen, but the primary polysaccharides are beta-D-glucans. Beta-glucans come in various forms, but the main one in fungi have what is known as 1-3,1-6 branching also referred to as (1-3)(1-6)beta-d-glucans. These are specific to fungi and yeast. Oats also contain beta-glucans, but they have a different branching structure, which are (1-4)beta-d-glucans.

This is important because the bulk of the medicinal mushroom research is based on the effects of these beta-glucans.

If the important compounds are beta-glucans, why are companies still measuring polysaccharides?

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Polysaccharide Fillers - Alpha-glucans

Another group of polysaccharides are alpha-glucans. These are compounds like glycogen, dextran, pullulan and starch. What we've discovered is that the polysaccharides in many so-called mushroom products are made up of alpha-glucans and not beta-glucans.

Where Polysaccharide Testing Falls Short

Beta-glucans and alpha-glucans in medicinal mushroom products
McCleary, B. V., & Draga, A. (2016). Measurement of Beta-Glucan in mushrooms and mycelial products. Journal of AOAC International, 99(2), 364–373.

If you look at the table above, you will see an alpha-glucan and beta-glucan breakdown of various medicinal mushroom products. Take note of specific mushroom products like sample #5, which is Reishi (Ganoderma lucidum). This particular sample tests high in alpha-glucans and very low in beta-glucans. Another prime example would be sample #12, which is Chaga (Inonotus obliquus). It expresses high amounts of alpha-glucans and little if any beta-glucans. Same applies for sample #8, Cordyceps sp. (ascomycete), which is dominated by high alpha glucans and small amounts of beta-glucans. The Nammex report also showed similar results.

On paper these products can tout high polysaccharide amounts (alpha-glucans + beta-glucans) but in reality the majority of those polysaccharides come from alpha-glucans in the form of starches and fillers. Those alpha-glucans provide no medicinal benefit.

This concept is extremely important to understand when it comes to medicinal mushroom products. It is quite concerning because many products on the market tout polysaccharide numbers yet fail to mention any beta-glucan numbers.

The Importance of Beta-glucan Testing

As the beta-glucans are the important polysaccharide in these fungi, it is vital that beta-glucan testing be done instead of polysaccharide testing to properly qualify medicinal mushroom products. The Megazyme method, developed by Dr. Barry McCleary at Megazyme International, has been used by the USDA and other peer-reviewed research papers to precisely measure the beta-glucan and alpha-glucan content in mushrooms. It can test all types of basidiomycete products like mushroom powders, mushroom extracts and mycelium powders. It detects soluble and insoluble (1-3)(1-6)beta-D-glucans and even quantifies the alpha-glucans, which are starches, so we can see if products contain fillers like grain.

High Polysaccharides ≠ Good Quality

A common trend you see in the medicinal mushroom industry are various brands claiming that their medicinal mushrooms products contain high amounts of polysaccharides. This looks and sounds great on paper but this can be very misleading considering that polysaccharides can also come from starches.

For example, products#2, 3, 8 and 12 in the table above are actually mycelium products that are grown on grain. They all can tout >60% polysaccharides but the polysaccharides are mainly coming from alpha-glucans in the form of grain starch and the products contain very little beta-glucans. Thus, the majority of your money is spent on alpha-glucans instead of beta-glucans, leaving you with a less potent medicinal mushroom product that is primarily grain.

This is why it’s imperative that you do your own research into exactly how the product is made and make sure to look for products that measure beta-glucans. Beware that products grown in North America are almost always mycelium grown on grain.

If you're curious, for less than $5 you can perform an iodine starch test on your medicinal mushroom product to verify if it contains any starchy fillers.

Final Thoughts

It is extremely important to understand that there is a difference in polysaccharides and that measuring polysaccharides for medicinal mushroom products is meaningless. High polysaccharides is not an indicator of quality and could actually be an indicator of poor quality.

A medicinal mushroom product should quantify the beta-glucans so you know the important medicinal compounds that much of the research is based around are present. This will help you in making an honest decision when selecting the right mushroom product.

At Real Mushrooms, we use the Megazyme method to measure beta-glucans and starch on all our products to show the potency and to confirm that they contain no fillers or grains.

Have questions or comments? Ask us below.


  1. Friedman, M. (2016). Mushroom Polysaccharides: Chemistry and Antiobesity, Antidiabetes, Anticancer, and Antibiotic Properties in Cells, Rodents, and Humans. Foods, 5(4), 80.
  2. Sari, M., Prange, A., Lelley, J. I., & Hambitzer, R. (2017). Screening of beta-glucan contents in commercially cultivated and wild growing mushrooms. Food Chemistry, 216, 45–51.
  3. McCleary, B. V., & Draga, A. (2016). Measurement of ß-Glucan in mushrooms and mycelial products. Journal of AOAC International, 99(2), 364–373.
  4. Biomolecules: Carbohydrates - Polysaccharides
  5. Chilton, Jeff, Nammex, 2015. Redefining Medicinal Mushrooms.
Skye Chilton
Skye is the founder of Real Mushrooms. Read more about his story into medicinal mushrooms here. When he’s not spreading the word of Real Mushrooms, he enjoys mushroom foraging, bouldering, cooking, gardening and hiking.

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