Powered by Mushroom Mycelium

Why All Host Defense Supplements Are Powered by Mushroom Mycelium

Originally posted on hostdefense.com.

We are all students of nature. And nature has an enormous depth of knowledge that we have barely tapped into. 

At Fungi Perfecti®, one of the most important things we’ve come to understand is that mycelium is a vast ecological network - a cellular network that has a far-reaching and significant impact on everything in its path. 

The activities of mycelium help heal and steer ecosystems on their evolutionary path, acting as a recycling mechanism to nourish other members of the ecological communities. By cycling nutrients through the food chain, mycelial networks benefit the soil and allow surrounding networks of plants and animals to survive and thrive. 

Increasingly known as the “wood wide web”, mycelium can be found underfoot with nearly every footstep on a lawn, field, or forest floor. It has been concluded that as much as 90% of land plants are in a mutually beneficial relationship with mycelial networks. Without fungi - without mycelium - all ecosystems would fail.

Mycelium and mycological applications have enormous potential to benefit the health of both people and planet. We are committed to continuing our research efforts to find new and innovative ways to build bridges between mycological applications to both human and planetary health.*

At Fungi Perfecti and Host Defense, We Follow the Science

One of the most significant outcomes of our research has been discovering the value of mushroom mycelium. Mushroom mycelium is the metabolically-active and longest living structure of the mushroom organism and contains numerous novel compounds shown to benefit human health. Years of industry-based research, along with both internal and third-party testing, demonstrates that mycelium-based supplements offer significant immunological support.* 

Benefits of Mushroom Mycelium*

Beneficial mushrooms have been used for centuries to support human health. From cognition and memory to energy and stamina, from sleep and cardiovascular support to support for liver health and the microbiome, the various species of beneficial mushroom cover a wide range of system-specific needs. One thing they all have in common is that beneficial mushroom mycelium and fruit bodies have been shown to support an engaged and modulated immune response.*

Mushroom Benefits at a Glance

At Fungi Perfecti® and Host Defense®, we follow the science. And years of research demonstrates that our mushroom mycelium-based supplements uniquely activate and balance immune activity. Read on to learn why we use mushroom mycelium in all of our supplements!*

What is Mushroom Mycelium?

A better understanding of the role of mycelium in the mushroom life cycle helps inform consumers about the benefits of mycelium. Mushrooms are a type of fungal organism with a three-stage life cycle that is similar to the different stages found in plants. Mycelium is the primary stage of the mushroom life cycle and longest living part of the organism. It consists of myriad intricate filaments that are only one cell-wall thick. Despite its delicate stature, mycelium is quite formidable. It grows for months, years, potentially centuries, and navigates through a sometimes inhospitable ecosystem. It is capable of expanding its reach through a habitat filled with millions of microbes while communicating chemically with the surrounding environment, devising complex chemical responses to whatever challenges it encounters.

Video by After Skool.

Eventually, when the circumstances are favorable, mushroom mycelium generates a fruit body - the above-the-surface, easily identifiable part of the mushroom organism. The process of producing a mushroom fruiting body requires that the mycelium maintain a highly active immune response to prevent pathogens from harming it. Meanwhile, the mushroom fruit bodies that eventually form, much like many flowers or fruits, can be highly perishable. For example, the oyster mushroom rots in just a few days. This is in stark contrast to the mycelium that generated it which can live for months, years, or decades.

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Mushroom Life Cycle

Mushrooms are a type of fungal organism with a three-stage life cycle that is similar to the different stages found in plants:

The Mushroom Life Cycle

Fungal Spores

Reproductive cells, similar to the seeds of a plant, the spores are what initiate fungal growth by ‘sprouting’ mycelium.

As with seeds that sprout into plants or develop into trees, a mushroom spore has been released from the fruiting body of another fungal organism as a means of reproduction. Under the best of conditions, spores can germinate in a matter of days, but typically take 2-3 weeks. Once germination begins, threads of mycelial hyphae begin to stretch out and grow, consuming and digesting the surrounding nutrient sources  - or “substrate” - as sustenance for further development.


The actual living organism, mycelium presents as an intricate web of root-like filaments. Mycelium is the primary “plant” portion of the mushroom. 

Mycelium consists of thousands of delicate, interwoven filaments, just one cell-wall thick, with highly active cells that serve many important functions, including acting as the immune response of the fungal organism. While spores exist to sprout mycelium, and fruit bodies come and go for reproductive purposes, mycelium represents the primary ‘body’ stage of existence in the fungal organism's life cycle. 

Mycelium supports the growth of the “flower”, known as the fruiting body, as a seasonal reaction to environmental stimuli. Mycelium is like the “mother plant” of a perennial, one in which the mother continues to live for many years, while the flower - or in this case, the fruiting body - blooms seasonally and then dies.

Mycelium Time Lapse © Dr. Patrick Hickey, 2008.

Time lapse video showing how nuclei (in green) and membranous organelles (in red) travel through mycelium. Like an underground highway, mycelium allows for dynamic transport of nuclei, organelles, and mitochondria. This is the manner in which mycelium communicates with its surrounding ecosystem. © Dr. Patrick Hickey, 2008.

Fruit body

The temporary, reproductive stage that comes and goes multiple times during the life of the fungal organism is the fruit body.

The fruit body is the easily-identifiable, above-the-surface “fruit” that we typically think of when we think of a mushroom. The mushroom fruit body is the reproductive stage that produces spores, similar to how a plant’s flower - or “fruit” - produces pollen or seeds in order to reproduce and propagate the species. And just like flowers and fruit, a mushroom fruit body is a temporary but recurring part of the plant’s overall life cycle as long as the environmental requirements are met.

Mushroom Lifecycle Timeline

Generalized timeline of when the fungal organism is most biologically active.
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Facts About Mushroom Mycelium

Because of the delicate, filament-like appearance of the mycelium, people sometimes assume it is nothing more than a root system designed to support a fruiting body. While it’s easy to dismiss the vast network of mycelial filaments under the surface, it’s important to understand that the mycelium represents the primary function of the organism.

  • Mycelium is the highly dynamic stage of the mushroom life cycle. Mycelium is the primary “plant” portion of the mushroom, while the fruit body is the temporary “flowering” part of the mushroom life cycle that releases spores for reproduction. 
  • Mycelium is the longest living part of the organism. Depending upon the species, mycelium can remain highly dynamic and metabolically active for ~95% of the overall life cycle, while fruiting bodies often represent less than 5% of the life cycle timeline. 
  • Mycelium serves as the immune response that supports not only the health, vitality, and immune response of the fungal organism, but also supports the health of the surrounding ecosystem. Scientific research, targeted studies, and widespread use in holistic treatment plans demonstrate that when harnessed in the form of supplements, human beings also benefit from the significant health-supporting power of mushroom mycelium.*
    Mycelium is Immunologically Active*
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    A Tale of Two Mushrooms: Mycelium vs Fruit Body

    If presented with two pictures, one of a mushroom fruit body and one of mushroom mycelium, and asked to point to the mushroom, most people would point to the fruit body without hesitation.

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    Fungi Anatomy

    Because mushroom fruit bodies are so easily identifiable for the majority of people, and there is much less awareness outside of mycology circles regarding mycelium, it’s easy for mushroom supplement companies to emphasize the importance of the fruit body when marketing their products. And similarly, it’s easy for those same mushroom supplement companies to dismiss the use of mycelium as somehow less beneficial than fruit body-only supplements. They will often put particular emphasis on the high beta-glucan content found in mushroom fruit bodies. But the truth is, both mushroom mycelium and the mushroom fruit body offer benefits to human health.*

    Mushroom Mycelium vs Mushroom Fruit Body

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    Mushrooms and Beta-glucans

    Part of the immunological activity produced by Host Defense® mushroom mycelium-based supplements is due to beta-glucan content, but there are also a wide range of polysaccharides and novel compounds responsible for immune activation and modulation. Singling out beta-glucans as the only active compounds fails to account for the complex chemistry of a mushroom mycelium-based supplement formula.* 

    Singling out beta-glucans as the only active compounds is misleading. Beta-glucans are  a classification of compounds, structurally termed as polymers, with hundreds of different beta-glucan shapes and sizes. Some beta glucans are biologically active and some are not.  This is because every sugar linkage comprising a beta-glucan polysaccharide can have a varying number of units, attached at different points to the sugar unit. The inherent complexity in their structure is unable to be characterized by current assay methods, the standard which is paradoxically used in the industry.

    Additionally, the reported beta-glucan values from several independent laboratories vary greatly even when identical assays are performed on identical samples. The most commonly employed assays for determination of beta-glucan content can only detect soluble beta-glucans; the insoluble beta-glucans remain undetected. Beta-glucans differ in their solubility depending on their size, functionality, and interaction with other molecules. In agreement with other organic chemists specializing in beta-glucan analysis, we have concluded that the currently employed methods are unreliable. 

    This is why we don’t include beta-glucan content on our labels. Stating a percentage on our labels when we know each methodology and each laboratory would yield a different result would be misleading to the consumer. There is no uniform, validated methodology in the industry. This makes us reluctant to make any claims on our product labels, and makes any purported beta-glucan levels listed for any mushroom product dubious.

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    Looking Beyond Beta-glucans

    The immune system is activated multifactorially by many components in mushrooms. Beta-glucans are just one variable. There are a variety of other bioactive compounds; many of which work cooperatively to optimize multiple aspects of health and wellness. The efficacy of a multi-constituent approach has been positively confirmed in the scientific literature. Many of these active ingredients are not water soluble, meaning that they are not pulled out by hot water extraction. The inclusion of these beneficial co-ingredients increases the overall beneficial effect. These constellations of complementary constituents are the foundation of our Host Defense® mushroom mycelium-based supplement line.*

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    How We Grow Mycelium

    Given that mycelium is a one cell-wall thick, delicate-yet-resilient structure that thrives below the surface, you might be wondering how we are able to both grow it in a sterile lab environment and also harvest it for use in supplements. In order to grow mycelium for use in Host Defense® supplements, it requires both a food source and specific conditions in order to grow and thrive.

    How We Grow Mushroom Mycelium

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    Fermentation and Substrates

    The process to grow mycelium in a controlled setting is not unlike that of several other well-known functional foods: 

    • Tempeh is made through a natural culturing and fermentation process in which a fungal organism binds to and ferments soybeans until tempeh is formed. 
    • Yogurt is formed when probiotic bacteria are introduced to milk and allowed to ferment.
    • Kombucha is formed when a mix of sugar and tea are fermented using a culture of bacteria and yeast (a fungal organism). 

    In each of these instances, the primary substrate is fundamentally converted as the primary ingredient digests and metabolizes the substrate. The process of fermentation makes the end result appear very different from the original individual ingredients. And in addition to the original nutritional profile, the newly fermented final result also offers a greater range of health benefits.*

    The process of growing mushroom mycelium is similar to how fermented foods like tempeh, yogurt, and kombucha are produced. For each of those highly beneficial foods, a growth medium called a “substrate” is introduced as a food source for the bacterial and/or fungal organisms.* 

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    Growing Mushroom Mycelium Using Substrates

    A substrate is also required in order to grow mushroom mycelium. At Host Defense®, we introduce organic brown rice to our organic mushroom mycelium. The mycelium absorbs the nutrients of the substrate as it consumes and digests the rice. While the mycelium ferments the substrate, it is converting it, creating a dense matrix of mycelium and “myceliated” fermented rice that becomes nearly impossible to separate. Together, the mycelium and fermented - or “myceliated” - rice form a new substance, just like tempeh which, once fermented, no longer resembles soybeans.

    Growing Mushroom Mycelium on Brown Rice Substrate

    Why We Use Brown Rice as a Substrate

    At Host Defense® we grow our mushroom mycelium on organic brown rice for a number of reasons:

    1. Organic brown rice is well-tolerated by most people.
    2. It serves as a nutritious food-source for the mycelium.
    3. It converts into an entirely new and highly beneficial spectrum of compounds once it’s been fermented by the mycelium.* 

    Some vendors in the mushroom supplement space would argue that mycelium grown on a rice substrate is not useful for consumers. For example, you may have heard that mushrooms used in supplement products need to be grown on wood logs - or similar to how they grow in the wild - in order to have a full nutritional profile. However, mushroom mycelium and fruit bodies are two distinct parts of the fungal organism and require two distinct grow methods in order to be harvested for use in a mushroom supplement product.

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    Benefits of Mycelium and Myceliated Brown Rice*

    There are hundreds of articles published in the scientific literature demonstrating the health enhancing value of mushroom mycelium grown on grain substrates such as organic brown rice, including a 2019 NIH funded study confirming the immunologically supportive activity of Host Defense® Turkey Tail mycelium-based capsules.*  Research confirms that the beneficial mushroom mycelium and the fermented substrate used to grow our mycelium are both immunologically active.*

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    Mycelium and Fermented Substrate are not “Fillers”

    Host Defense® uses the mycelium and the fermented rice metabolites in all of our supplement formulas. This provides a far greater range of metabolically active compounds than what can be found in mushroom fruit bodies alone. Research has shown that in Host Defense® products, both the mushroom mycelium and the fermented substrate are immunologically active and offer a complementary array of health-supporting compounds.* 

    Consumers should keep in mind that it is not possible to separate mushroom mycelium from the substrate on which it’s grown under normal circumstances. Similar to yogurt, in which beneficial bacteria like Lactobacillus cultures milk, these two nutrient sources exist as a living, interconnected matrix. Alongside the pure mycelium, the cultured, fermented rice substrate becomes a new, integrated functional food providing highly effective support for immune function.*

    Many companies that just use mushroom fruit bodies in their supplements would have consumers believe that the fruit body is the only part of the mushroom that offers health-supporting benefits. Some have gone so far as to develop a marketing strategy solely around the idea that mushroom mycelium and the substrate used to grow it are nothing more than “filler”. They claim that mushroom mycelium and its fermented substrate “offer no health-supporting benefit”. These claims ignore the growing body of evidence of research.* 

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    Immune Benefits of Mycelium and Fermented Substrate*

    In 2019, our researchers at Fungi Perfecti® teamed up with the immunology experts at Natural Immune Systems, Inc. (NIS), a 3rd party, independent lab in Oregon, to investigate the health benefits of both mushroom mycelium and the fermented rice-substrate on which the mycelium used in Host Defense® products is grown.* 

    Analyzing the Research

    This breakthrough research objectively demonstrates the efficacy of our products. The open-sourced, peer-reviewed study verifies that:

    • Mushroom mycelium is “very potent in terms of triggering immune cell function.”*
    • The fermented substrate, even when separated from pure mycelium, is highly active in supporting natural immune function.
    • Pure mycelium and fermented substrate each offer unique yet complementary health benefits. 
    • The immune-supporting benefits of mushrooms are generated from a very wide range of constituents, not just beta-glucans.*
    Immune Benefits of Mycelium and Fermented Substrate*

    With regard to the impact of this research, one independent reviewer stated, “…the possibilities seem a bit underestimated by the authors. The study is well done, it’s subject is new and original, and the results are relevant.”

    Furthermore, in another study conducted by NIS, it was found that the mycelium and the cultured rice substrate are active in different ways, each conferring unique and complementary immune benefits.* The same immune assays were performed on organic brown rice that had not been fermented by mushroom mycelium. With the plain, uncultured rice, no significant immune activity was detected. This data definitively demonstrates that cultured mycelium and its matrix of fermented organic brown rice is extraordinarily active in supporting immunity.* 

    Research Conclusions

    Research has conclusively shown that in Host Defense® products, the mushroom mycelium and the fermented substrate are both immunologically active and offer a complementary array of health-supporting compounds.* 

    "The evidence is clear - and continues to accumulate - that mycelium offers significant immunological benefits."* 
    — Paul Stamets 
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    Host Defense Uses the Highest Quality Mycelium

    Since the beginning, Fungi Perfecti® and Host Defense® have been leading the industry in researching mycelium for immunological and ecological applications. We employ an internal team of mycologists, researchers, and medical professionals. Additionally, we collaborate with third-party labs to independently verify our findings.* 

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    Our Mushrooms are USA-Grown and Sustainably Cultivated

    At Host Defense®, we are confident that we offer the highest quality USA-grown, organic mushroom mycelium supplements on the market. In addition to third-party testing that verifies the efficacy of our mycelium-based supplements, all of our products are also verified for identity, purity, composition, and strength by independent labs that use internationally recognized testing methods. We validate the authenticity of our mushrooms by both genetic and biochemical assays, and we test for pesticides, heavy metals, and microbiological contaminants to verify safety. Our products are USDA organic, non-GMO, vegan, gluten-free, and sustainably packaged with a focus on environmentally conscious materials.

    Certified Organic, Washington Certified Organic, Non-GMO, Vegan, Gluten-free
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    Commitment to Further Research

    Transparency is important to us. As part of our foundational value system, Fungi Perfecti® and Host Defense® is dedicated to furthering research on beneficial mushrooms – including mushroom mycelium and the fermented substrate used to grow it. Our ongoing dedication to science and furthering the field of mycology extends beyond our rigorous research initiatives to employing a dedicated team of mycologists, researchers, and medical professionals, including 3 PhDs and 3 other full-time researchers. These highly trained scientists are committed not only to testing the efficacy of Host Defense® products, but also to looking for new and innovative ways to utilize the immune-supporting benefits of the mushroom organism.

    At Host Defense® we follow the science. And years of industry-based research, along with both internal and third-party testing, demonstrates that our mycelium-based mushroom supplements offer significant immunological support.* 

    "In my scientific opinion, mushroom products not incorporating mycelium are at a decided disadvantage, given the results of recent research."* 
    — Paul Stamets 


    At Host Defense®, we use mushroom mycelium in ALL of our products – because it works!*
    Fungi Perfecti, LLC.


    *These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.

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