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Medicinal Mushroom Benefits: Mycelium vs Fruiting Body

Mycelium vs Fruiting Body
Written by Real Mushrooms - Updated: May 22, 2024

To Benefit from a Medicinal Mushroom, You Need to Know What You’re Getting 

Not all fungal products are equal. Functional "mushroom" products generally contain EITHER the mushroom (fruiting body) OR the mycelium (vegetative body). Notice the quotes on mushroom as currently there is no function mycelium category so mycelium based products are also contained under the mushroom umbrella even though mushrooms and mycelium and two very distinct and different parts of these fungal organisms. 

If you actually want to benefit from the bio-compounds in these fungi, it is extremely important know which part you’re getting when you purchase a supplement. And with so many products on the market making claims about ingredients and efficacy, it can be challenging to understand what will truly support your health.

Read on to learn the myths and facts about medicinal mushroom supplements to get the most functional health support from fungi. The bottom line is that both the scientific research and respected practitioners in the field confirm that the medicinal value is much higher when using the mushroom, rather than the mycelium.

Listen below to master clinical herbalist, Dr. Terry Willard, as he summarizes the issue:



Fruiting Body, Mycelium, & Marketing Hype

The way many supplement brands market and sell their fungi products is cause for concern. If consumers don’t know what to look for when buying a medicinal mushroom supplement, they may easily be misled by the packaging, naming, and labeling of the vast products available. 

It can be difficult to distinguish a real mushroom extract made of the mushroom (fruiting body) from one made of the mushroom's "root" structure, mycelium. Reading a supplement’s packaging and nutritional labels won’t necessarily tell you the whole story either.

Mushroom product labeling requirements from the US Food and Drug Administration (FDA) tell manufacturers to clearly distinguish whether the product contains actual mushroom (the fruiting body) or just the mycelium in any food or supplement product. But not everyone follows these rules and this is low on the FDA's enforcement priorities.  

In 2017, The American Herbal Products Association (AHPA) released labelling guidance for Fungi Dietary Ingredients. This is not enforceable but gives recommendations on how Fungal based products should be accurately labelled to clearly inform the consumer on what is in the product.

Too often, brands disguise the true nature of their products and misdirect consumers who want to buy effective medicinal mushroom products. Here we will separate the myths from the facts about mushroom terminology, their active compounds, and the marketing hype, to give you the information you need to buy a supplement with the most medicinal mushroom benefits.

To reap these benefits, you need a supplement with high concentrations of the parts of the fungi that offer the most therapeutic compounds. This article gives you the knowledge you need to make informed purchasing decisions, so you can truly experience the adaptive health benefits of medicinal mushroom supplementation.

Fruiting Body vs. Mycelium

The Difference between Fungal Parts

A mushroom is the “fruiting body” of a fungal organism called a basidiomycete (except in the case of the cordyceps mushroom — they are an organism called an ascomycete). Basidiomycetes have three distinct parts that develop throughout its lifecycle: spore, mycelium, and mushroom.

The spores are in the surrounding air all around us, and under favorable conditions, these will germinate and begin to grow branching filaments called hyphae. As the hyphae continue to grow, they will fuse together to form mycelium.

Mycelium is an underground network that expands and feeds off of organic plant matter. This phase of the basidiomycetes’ life cycle is the vegetative stage or the vegetative body of the organism. During this time, the mycelium produces enzymes that break down the plant material in its growth radius and recycles it into beneficial compounds that return to the soil.

In nature, this typically means that mycelium will form large networks of fungal matter by breaking down wood, logs, leaves, and other plant matter. The plant matter on which fungi feed is commonly referred to as the substrate. The mycelium becomes entwined in whatever substrate it’s in, making an inseparable mass of substrate and mycelium.

If environmental conditions are right, the mycelium will produce a mushroom, a.k.a. the fruiting body. The mushroom is actually the reproductive structure of this organism. When fully mature, it produces spores that, when distributed across plant matter, will allow for the creation of new mycelial networks, and ultimately the spread of the fungus.

Mycelial networks can live for hundreds, if not thousands of years and spread across vast distances. In fact, the largest organism on earth is a mycelial mat of a honey mushroom in eastern Oregon that is 890 hectares in size and over 2,000 years old!

It is important to reiterate that just as a mushroom is not mycelium, mycelium is also not a mushroom. These terms are not synonymous and should be accurately differentiated.

From spores to fruiting body - mushroom life cycle

Identifying Fillers in Your Supplement

Read the ingredients on the mushroom or mycelium supplement package to see which part of these fungi the producer used. Based on the labelling, many times it is unclear. The product could be any combination of mycelium, mushroom, sclerotium, spore, and substrate matter, dried, ground into a powder and then potentially extracted. 

Using all the parts of the fungi might seem like an effective way to reap the most benefits. However, there are parts of the basidiomycete, like the mushroom (fruiting body), that contain more active beneficial compounds than others. The mycelium, on the other hand, is typically grown on a solid substrate which will become part of the finished product. 

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The majority of commercial producers grow mycelium on grains like rice, oats, or sorghum. Therefore, all that grain becomes inseparable from the mycelium and remains in the final product, leading to high amounts of starch.

When myceliated grain forms the bulk of a supplement, the grain acts as a filler and "dilutes" the product because it doesn’t contain any active compounds. Myceliated grain dramatically reduces how much beneficial compounds are in each serving of your supplement.

Mycelium on Grain. This is not the fruiting body
Mycelium grown on grain

The Key Medicinal Compound in Mushrooms: Beta-Glucans

Functional mushroom benefits are derived from their active compounds, which are found in abundance in the mushroom (fruiting body) itself, and less so in the mycelium. The most important of the key compounds in fungi are called beta-glucans, and they offer a host of health benefits.

Current research shows that beta-glucans’ most important benefit to our health is to modulate the immune system. Additionally, they can help regulate blood sugar, improve feelings of fatigue, and increase overall endurance. 

In some cases, beta-glucans can have a positive effect on malignant conditions based on their ability to increase certain immune cells that increase autophagy.*

Also, consider that medicinal mushrooms have been used for thousands of years in Traditional Chinese Medicine (TCM), with varieties like reishi, shiitake, maitake, lion’s mane, turkey tail, and cordyceps being the most revered for their powerful health benefits. TCM practitioners still use medicinal mushrooms to treat a host of different ailments and health conditions.

Beta-Glucans: Mycelium vs Fruiting Body

The chart below shows the significant difference between mushroom (fruiting body), pure mycelium and myceliated grain. Pure mycelium can be produced by growing the mycelium in a liquid substrate instead of a solid substrate.

This is known as liquid fermentation.

At the end of the growing process, the liquid can be drained off yielding pure mycelium. However, most producers of mycelium-based products grow the mycelium on a grain substrate. 

The Percentage of Beta-glucans and Alpha-glucans in Cordyceps Fruiting Body and Cordyceps Mycelium

Beta-glucans Alpha-glucans
Cordyceps militaris mushroom 34.36% 1.65%
Cordyceps Cs-4 (Pure mycelium) 7.58% 1.61%
Cordyceps mycelium grown on grain 1.5% 64%

Analytical data courtesy of Nammex™

The consistency of Alpha-glucans content between mushrooms and pure mycelium confirms that the extremely high alpha-glucans in myceliated grain are from the undigested grain in the final product. 

A helpful example of visualizing myceliated grain is the food product tempeh. Tempeh is a traditional cake-like Indonesian food that is made from cooked soybeans fermented with a fungus. 

Grain-based Tempeh
Grain-based Tempeh

The producer packs the tempeh and forms it into patties or logs.  As the fungus grows on the the soybeans it becomes as inseparable mass, which they sell as a meat replacement food.  Similarly, with myceliated grain, the resulting finished product retains BOTH the mycelium and the grain substrate it grows on.

Is that Supplement Made of Real Mushrooms?

Too often, supplement brands bring to market medicinal mushroom products with claims of being pure mushroom extracts. However, the product could be any combination of mushroom (fruiting body), mycelium, sclerotium, spore, and substrate matter. There are many documented cases of mushroom supplement packaging and labeling that obscures or outright misrepresents exactly what the buyer is getting. This marketing misstep causes consumers a lot of confusion and jeopardizes the integrity of the supplement market.

Reishi fruiting body
Reishi fruiting body

Investigating Mushroom Supplement Integrity: Reishi Products

Part of the issue facing the mushroom industry is the lack of standardized testing for various mushroom types. However, Reishi mushroom (Ganoderma lucidum) is an exception. 

Given its long-standing use in traditional Chinese medicine, researchers have developed reliable testing methods for identifying Reishi compounds in products. 

Using these proven testing methods, six scientific researchers conducted and published a study in partnership with the US Pharmacopoeia to evaluate 19 reishi mushroom supplements purchased online in the U.S.A. from websites such as Amazon and Ebay. Only FIVE of the 19 supplements (26.3%) contained genuine reishi. The sample of products evaluated in the study included six mushroom powders, one mushroom powder with added polysaccharides, one reishi mycelia product and eleven extracts. The results of this reishi supplement study indicates that several commercially available mushroom supplements do not contain what the consumer expects based on the product information and labels. 

Additionally, ConsumerLab investigated reishi supplements and uncovered contradictions between product labelling and product contents. One of the seven top-selling brands they analyzed made claims on its label that could not be supported. The brand’s product name includes the term “mushroom” and the packaging features an image of the mushroom (fruiting body) on the front. However, the product itself contained reishi mycelium only and no mushrooms whatsoever.  

ConsumerLabs went on to say that, “Its chemical fingerprint matched that of mycelium, but the inclusion of “mushroom” in the product’s name and the image of fruiting body, rather than mycelium, on the front label could lead a person to believe that the product contains reishi fruiting body and to expect concentrations of compounds normally found in the fruiting body. In fact, [the product] contained hardly any beta-glucan; instead, it contained the highest concentration of alpha-glucan, which is simply a polysaccharide from the grain (brown rice) on which the mycelia were grown.”

Fungi Buyer Beware: What to Look Out For

The above examples illustrate an ongoing problem within the medicinal mushroom industry as well as supplements in general. Consumers need to be aware of what they’re getting. 

Real Mushrooms only uses extracts from the mushroom (fruiting body) itself and doesn’t include any substrate matter or fillers in its formulation. We label our products to show exactly what ingredients we include and from what part of the fungi. Further, we list the percentage of Beta-Glucans in each serving.

By carefully reading the ingredients on any supplement label, by selecting a product with the mushroom (fruiting body) as the primary content, and by choosing organic suppliers who list the percentage of medicinal compounds (Beta-Glucans) in each serving, you can improve your chances of buying a high-quality mushroom extract powder with effective medicinal concentrations. 

Therefore, to get the most potent and high-value medicinal fungi supplement, look for extracts made from the mushroom (fruiting body) which also specifies beta-glucan content. Also, refrain from buying supplements that do not specifically state the part of the fungi they use. The ingredients label should say whether you are getting the mushroom, the mycelium, or a blend of both.

Without myceliated grain and other fillers, Real Mushrooms supplements deliver a high-potency dosage of medicinal beta-glucans per serving, the main active compound in mushrooms and mycelium. We list the beta-glucans content of all our products to show and guarantee you that they are present.

Nutrition Label Real Mushrooms Beta Glucans
A reliable fungi supplement should list the % of Beta-Glucans

How to Choose an Effective Mushroom Extract

A Mushroom Supplement Buying Guide

By understanding the difference between mushrooms and mycelium, you can cut through the noise and make an informed product choice. To know what you are getting and reap full benefits from these fungal wonders, shop with these guidelines in mind:


  1. Read the product's Supplement Facts panel and attempt to distinguish the true contents of the product.
  2. Select products that primarily contain the mushroom (fruiting body), not just mycelium, myceliated grain, or myceliated biomass.
  3. Avoid buying products that lack specific information about the plant part of the fungi (whether mushroom or mycelium).
  4. Look for an extract as extraction breaks down the fungal cell wall and improves bioavailability.
  5. Look for brands that list the beta-glucans content in their Supplement Facts panel. It's important for it to be in the Supplement Facts panel and not just in any marketing materials. 
  6. Ignore any polysaccharide numbers because polysaccharides also measure starches
  7. Make sure the ingredients are organically grown. 
  8. Always choose to buy from a trusted source. 

Real Mushrooms' commitment is to provide you with the very best quality and greatest possible potency of mushroom supplements. Read our story and Shop Real Mushrooms products to try our line of 100% real mushroom extracts that deliver all the health benefits of a real medicinal mushroom.

A person's hands selecting one of several varieties of packaged mushroom products displayed on a shelf, with a visible "Best Mushrooms for Anxiety" sign.

Real Mushrooms is the premier provider of organic mushroom extracts, verified for the beneficial medicinal compounds like beta-glucans and free from starchy fillers like grains. With over 40 years of mushroom growing experience, Real Mushrooms prides itself on providing a transparent source of functional mushrooms that you can trust. All the information provided on our blog has been reviewed by our science and medical team.

Disclaimer: The information or products mentioned in this article are provided as information resources only, and are not to be used or relied on to diagnose, treat, cure, or prevent any disease. This information does not create any patient-doctor relationship, and should not be used as a substitute for professional diagnosis and treatment. The information is intended for health care professionals only. The statements made in this article have not been evaluated by the Food and Drug Administration. Any products mentioned are not intended to diagnose, treat, cure, or prevent any disease. The information in this article is intended for educational purposes. The information is not intended to replace medical advice offered by licensed medical physicians. Please consult your doctor or health practitioner for any medical advice.