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The Hidden Truth About Mushroom Supplements

by Jeff Chilton
Home/Blog/Protect Your Mental Wellbeing During the COVID-19 Pandemic

Here’s all you need to know about the warning signs and health benefits of medicinal mushroom supplements…

Mushrooms have magic powers, also known as: “medicinal mushrooms,” used in popular supplements. However, not all mushrooms are created equal.

As a raw ingredient supplier of medicinal mushroom extracts for over 25 years, we have seen new growth from traditional supplement companies but also many new companies looking to add mushrooms to everything from coffee, chocolate, health bars, sports drinks, kombucha, and beer. You name it; someone is trying to put mushrooms in it.

Research on mushrooms has demonstrated immune support, brain health, boosting energy and relieving fatigue, and antioxidant activities.

In fact, there are thought to be over 126 medicinal functions produced by mushrooms.

Popular mushrooms that you may have heard about are reishi, shiitake, maitake, cordyceps, lion’s mane, chaga and turkey tail.

man holding medicinal mushrooms

However, if I told you that the mushroom supplement you are taking did not contain mushrooms and in fact was mostly grain starch, how would you react? Sad? Mad? Total disbelief? Well, I hate to break it to you, but mushroom supplements with grain-like starches are more common than you might think.

The Fungus-producing Life Cycle of a Mushroom.

First, we need understand the life cycle of these fungal organisms. What many companies and consumers don’t know is that the Medicinal Mushroom category encompasses more than just mushrooms.

The life cycle revolves around 3 main stages: spore, mycelium and mushroom.

mushroom life cycle

Stage 1: Mushroom begins as a spore

The mushroom cycle starts when a spore germinates and forms a thread-like tube called a hypha.

Stage 2: Mushroom hypha grow into mycelium

Multiple hypha fuse together to form a network called mycelium. Mycelium is considered the vegetative body. In nature, mycelium grows into a nutrient base like wood, fallen leaves and other spent organic matter.

Stage 3: Mycelium body turns into a mushroom

When conditions are right, the mycelium will produce a mushroom, which is also known as the fruiting body. When the mushroom is fully mature, it will release spores and the life cycle will start over.

The Fungal Parts Sold as Medicinal Mushrooms

Traditionally, only mushrooms were used medicinally. Today, other fungal parts are sold as nutritional supplements, and this is where the confusion begins.


Mushrooms have been used for thousands of years in Traditional Chinese Medicine, and scientific studies have documented powerful medicinal activities, especially immunological support from the beta-glucans in the mushroom cell walls. The majority of the medicinal mushroom research is based on the mushroom or fruiting body.

Reishi mushroom is revered as one of the most important tonic herbs and mushrooms generally are an important part of the Asian diet.


In China, companies now grow reishi mushrooms specifically for the spores and the spores have become worth more than the mushroom. They process the spores by a method that cracks the hard outer shell. They then call it a “cracked” spore.  Although there are many claims made about their activity, there is still no solid research to back up these claims.

dusty mushrooms

In the US, some companies claim spores are in their products as part of a “full spectrum” or “whole life cycle” product. Unfortunately, unprocessed spores have been shown to have no medicinal function and pass right through our digestive system unscathed.


In China, mycelium is grown in large tanks of sterile liquid media (water and nutrients). This process is known as liquid fermentation. After 3-6 days of growing, the liquid media is removed and what remains is 100% pure mycelium. Scientific research has shown that pure mycelium does have some medicinal value similar to mushrooms.

The most famous of these pure mycelium products is Cordyceps Cs-4. China developed this pure mycelium product in the 1980’s when the price of natural Cordyceps sinensis (Caterpillar Fungus) began to rise. This substitute for the wild Cordyceps sinensis is now produced in mass quantities and has been shown to have similar qualities to the wild Cordyceps sinensis. Today, the wild caterpillar fungus is valued at over USD$20,000/kg, making it too expensive for the North American supplement market.

Research on pure mycelium is often used to justify growing mycelium on grain, however the two are in no way comparable.

Mycelium on Grain is NOT a full Mushroom

In the U.S., companies are growing mycelium on sterile grain in a laboratory. This process is historically used to make spawn, the seed to grow mushrooms.

Today, these companies harvest the mycelium and grain, dry it and grind it to a powder.

The grain cannot be separated from the mycelium, so although these products in general contain NO mushrooms, they are sold as a “mushroom” supplement.

The main labels may even say “mushroom”, with a picture of a mushroom, and often with a statement that they are made with 100% organic mushrooms.

Companies using this method often claim that the grain is completely consumed by the mycelium…but is that really true?

The Presence of Grain

In 2015, Nammex published a study called “Redefining Medicinal Mushrooms.” In this study we tested 95 products, including dried mushrooms, mushroom extracts, and 40 bottled products that were mycelium on grain. Since then we have tested over 100 more samples.

We specifically looked at beta-glucans, a form of polysaccharide, that are the primary active compounds in mushrooms and research has demonstrated that most of the benefits from medicinal mushrooms are derived from these beta-glucans. We were also able to measure alpha-glucans, another form of polysaccharide, which can be used to measure any grain in the form of starch.

These compounds were quantified using a new testing methodology from Megazyme International.

Our analyses demonstrated that whole mushrooms and mushroom extracts are high in beta-glucans, 25-60%, and low in alpha-glucans, less than 5%. Products made from mycelium on grain showed the exact opposite: low in beta-glucans, 0-12%, and high alpha-glucans, 30-70%. Our testing data was corroborated by two different commercial labs, including the lab of Megazyme itself.

This confirms that the mushroom mycelium is not consuming all the grain substrate and a large portion of it is ending up in the final product.

We further confirmed our findings by testing other common compounds found in mushrooms like triterpenes and ergosterol.

How to Tell if Your Product Contains Grain

Here are a few basic rules and tests for determining whether or not a “mushroom” product contains grains. This can often be hard to determine as many products do not properly indicate exactly what the product consists of. Here are some primary clues:

Does the marketing material or label say:

If you see any of these keywords, there is a good chance that the product is made from mycelium on grain. Using the simple test below will further confirm the presence of grain.

The Iodine Starch Test

One easy test you can do at home to confirm the presence of grain is to mix 1 gram of your “mushroom” product into 3 tablespoons of water. Then add 10 drops of standard iodine tincture from any drugstore or pharmacy.

If the mixture turns purple or black, then that confirms the presence of starch.

test tubes iodine

test tubes iodine

The Bottom Line

We believe in the amazing benefits of mushrooms, but as a consumer you must be very careful about the product you choose. Not only might it contain grain, but it also might not be consistent with the medicinal mushroom research. We sincerely hope this information is helpful and that you’ll be able to now judge the quality of a Medicinal Mushroom product.

Mushrooms image licensed under the Creative Commons.




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Jeff Chilton

Jeff Chilton

Jeff Chilton studied ethnomycology at the University of Washington, is a founding member of the World Society for Mushroom Biology and Mushroom Products, and a member of the International Society for Mushroom Science. His company, Nammex, was the first to offer a complete line of certified organic mushroom extracts to the U.S. nutritional supplement industry. […]