Mushrooms: Fruiting Body vs. Mycelium — The Truth About “Myco-Washing”
Walk into any supplement store or browse online for functional mushrooms — Lion’s Mane for focus and brain health, Reishi for stress, Turkey Tail for immunity — and you’ll find dozens of products competing for your attention. They all feature the same earthy imagery, the same and typical health claims, and the same premium price tags. But here’s the uncomfortable truth that aspects of the “mushroom” industry don’t want you to examine too closely: a significant portion of what’s being sold as “mushroom supplements” in the United States doesn’t actually contain any significant amounts of mushroom at all.
Instead, what you might be buying is something called “myceliated grain” — or as it’s known in the industry, “MOG (Mycelium On Grain)”. And the difference between MOG and a true mushroom is not a minor technicality. It’s the difference between ordering a jar of pure saffron and receiving a jar of saffron flavored rice. Same aisle. Same price. Completely different product.
What Is a Mushroom, Anyway?
Let’s start with the basics, because some “mushroom” companies in the industry have done a masterful job of muddying the waters.
A fungal organism has three main parts that may be compared to plant parts: the spore, functioning as the seed; the mycelium, similar to the roots; and the mushroom as the fruit. The mushroom, also called the fruiting body, is what most of us picture when we think “mushroom” — the cap, the stem, the part you’d find at a farmers’ market or growing from a log in the forest. This is the actual mushroom.
The mycelium, by contrast, is the root-like network that lives underground or within a substrate — a tangle of thread-like fibers that anchor and feed the organism/mushroom. Mycelium serves a critical biological function, but it is not the mushroom itself.
Mushrooms: Our Ancient Friends
The mushroom, or fruiting body, is the fungal part that humans have been eating for over 20,000 years. Our evolutionary relationship with mushrooms is very ancient. While there is extensive archaeological evidence for the consumption of fruiting bodies (mushrooms), there is no archaeological evidence that ancient humans harvested and consumed loose mycelia from soil or wood as a standalone food or medicine. From a survival standpoint, foraging for “wild mycelium” would be highly inefficient.
Historically the traditional medicinal use of fungi centers on the use of the ‘above ground” mushroom, not mycelium. Herbal Classics from the Han Dynasty written 2,000 years ago referenced use of the mushroom/fruiting body. In modern times a search on PubMed yields over 2,400 studies on the health benefits of mushrooms and the majority of this research has been conducted on the actual mushroom. Against this historical backdrop, it is only in the last 20 or 30 years that humans decided that mycelia grown on grain could be considered a “mushroom”.
Even the FDA thought it was important to clarify the fact that mycelium should not be considered the same as a mushroom. In 1976, The FDA issued the following policy regarding labeling of mushrooms:
“Any food in which mushroom mycelium is used should be labeled to state that fact. Labeling should not suggest or imply that the food contains mushrooms. For example, a soup in which mushroom mycelia is an ingredient should not be labeled or sold as ‘mushroom soup’ since that name by long customer understanding and usage is preempted by soup containing real mushrooms.”
More recently, both the American Herbal Products Association and the Natural Products Association have released guidance policies and petitions for the supplement industry to follow these same labeling practices to protect the public from confusing, false, and misleading claims. Although many manufacturers have started to correct their labeling, many selling mycelia products still show photos and graphics of actual mushrooms on the packaging and marketing.
The Quality Spectrum
To understand just how wide the gap is, picture it as a spectrum:
BestFruiting body extract
The actual mushroom, which is then extracted and sometimes concentrated. Rich in beta-glucans, triterpenoids, and a full array of bioactive compounds. This is what the science AND historical use of mushrooms is built on.
MiddleRaw mycelium
The root structure. Some beneficial compounds present, but at significantly lower concentrations than the fruiting body, with none of the maturation that occurs when a mushroom fully develops.
AvoidMOG (Myceliated Grain)
Mycelium that has been grown on grain and never separated from it. The resulting powder often is 30–60% common starch. This is not a mushroom product in any meaningful sense.
The leap from fruiting body, to mycelium, to MOG isn’t a small formulation difference — it’s the distance between a fine espresso and a cup of hot water that once sat near some coffee beans.
Enter MOG: The Leprechaun Riding a Pink Unicorn
Here’s where the story takes a turn into something that sounds more like a fairy tale than a compliant supplement label.
The MOG process works like this: manufacturers take bags of sterilized grain — typically white or brown rice or oats — and inoculate them with mycelium spores. The mycelium colonizes around the grain over several weeks. Then, rather than waiting for actual mushrooms to grow to maturity, the whole mixture — grain and all — is dried, ground into powder, and encapsulated.
There are usually no fruiting bodies in this matrix, no actual mushrooms. Just a blend of fungal root structures and common starch, processed and sold to you as a mushroom product.
When this practice began gaining traction in the U.S. over the past two decades, some manufacturers started getting creative with their justifications. The fermentation-like colonization process, they claimed, somehow transmutes the grain — transforming it into something functionally equivalent to real mushroom tissue. The mycelium, as suggested, magically changes the grain on a molecular level, imbuing it with all the properties of a mature fruiting body. Or some similar construct thereof.
It’s a compelling story. It’s also pretty much a fantasy. There is no peer-reviewed, reproducible scientific evidence that the MOG process transforms grain into anything resembling the bioactive profile of a mushroom fruiting body. In our minds, we picture this concept as something like a leprechaun riding a pink unicorn over a rainbow — charming, whimsical, and entirely detached from reality.
“There is no peer-reviewed, reproducible scientific evidence that the MOG process transforms grain into anything resembling the bioactive profile of a mushroom fruiting body.”
Some companies have started funding their own studies, attempting to “prove” that their fermented grain has shown immune benefits in a petri dish. However, the fermented grain is still not a mushroom. The fermented grain does not contain the 100’s of distinct mushroom active constituents that our body has learned to recognize over many millennia. They claim the product is similar to yogurt or tempeh. Yogurt and tempeh may be healthy foods, but they’re not mushrooms. And if someone took a $2 serving of tempeh and ground it up and put it into capsules, would you pay $40 for a bottle?
Myco-Washing: The Mushroom Industry’s Dirty Little Secret
You’ve heard of greenwashing — companies dressing up environmentally questionable products in eco-friendly language to win over conscientious consumers. The functional mushroom industry has its own version of this playbook, and we think of it as “Myco-Washing”.
Myco-Washing is what happens when a company takes a bag of grain, adds mycelium and ferments it, and then markets the result of this process using the full vocabulary of serious mushroom science — “adaptogenic,” “immune-modulating,” “bioactive,” “full-spectrum.” The packaging looks indistinguishable from genuine authentic mushroom products. The claims echo the same research. The price point is often identical or higher.
But at the end of the day, you’re largely paying premium supplement prices for fermented grain in a capsule. The economics alone should raise every eyebrow. High-quality mushroom fruiting body extract is expensive to produce because actual mushrooms require time, specific growing environments and cultivation techniques, careful harvesting & drying, and precision extraction. Myceliated grain costs a fraction of that — because grain is cheap and starch is cheap. When you pay $40–$60 for a “premium mushroom supplement” that is 50-70% oat or rice starch, you’re not investing in your health. You’re subsidizing someone’s grain budget.
What You’re Actually Getting in the Capsule
Independent laboratory testing of MOG-based products has produced some striking findings. When you analyze many popular “mushroom” supplements on the U.S. market, you find that most often, 30% to 70% of the capsule content is simply starch — the residual grain that was never transformed into anything remotely mushroom-like.
A key marker here is the – ‘beta-glucan’ content. Beta-glucans, found in mushrooms and some yeasts, are the primary and most researched bioactive compounds responsible for the immune-modulating, adaptogenic, anti-inflammatory, and other benefits associated with functional mushrooms. These are specifically characterized or named as β-(1,3/1,6)-glucans, which are structurally and functionally different from the β-(1,3/1,4)-glucans found in oats & barley. High-quality fruiting body extracts typically contain beta-glucan levels of 20–50% or higher. MOG products regularly test at 5% or less — if meaningful levels are detected at all.
What you will find in abundance in many MOG products is ‘alpha-glucans’ — the starch molecules from the colonized grain. Alpha-glucans from grain are simple carbohydrates with very little bioactivity and are not the same as the beneficial select 1,3/1,6 beta-glucans from mushrooms. When you see a product boasting high “polysaccharide” content without specifying beta-glucan levels, that should be a red flag. They may be counting grain starch as a featured ingredient under the polysaccharide nomenclature.
Some companies selling MOG are now attempting to discredit beta-glucan testing. While β-(1,3/1,6)-glucans are certainly not the only beneficial bio-actives in mushrooms (as we mentioned there are 100’s, including triterpenoids, polyphenols, antioxidants, and ergosterol) currently any food lab can run a standard “Megazyme test" to measure beta glucans. Analyzing other specific secondary metabolites is significantly more complex and requires advanced HPLC methods. So far there are only a few labs in the US with validated testing methods and those have not yet been “USP Standardized”. We support all efforts in the US to develop standardized methods for testing additional compounds in mushrooms, however so far this work is still in the beginning stages. Until then, beta-glucans remain the best option for determining the presence of real mushrooms and the potency of a product. Meanwhile, as MOG proponents discredit beta glucans, they are not labeling any specific mushroom bio-actives.
A Question for the Industry
Where is the Science?
Here’s a challenge for MOG producers, if beta glucan testing is invalid, what bio-actives are you testing for? Please reveal to consumers the science of which mushroom compounds are present in your products in significant amounts that are responsible for the beneficial effects you are claiming.
Why Does This Keep Happening?
MOG production is cheap. Cultivating actual mushroom fruiting bodies requires time, precise growing environments, proper substrate management, and careful harvesting. It’s labor-intensive and more expensive to do right. Growing mycelium on grain requires far less infrastructure, dramatically reduces production costs, and turns around product “material” quickly.
Also, MOG can be cheaply produced in the US. Producing actual mushrooms at a scale needed to supply supplement industry demand is not economically feasible in the US. The fact is that China is the world's leader in mushroom cultivation & production, consumption, and science and research. China has been cultivating mushrooms for over 800 years and 90% of the world’s supply is expertly grown there in rural mountain regions, in football field sized shade houses that mimic natural growing conditions.
For those of us who have spent a great deal of our careers in the US Dietary Supplement industry, which is constantly fighting a rhetorical battle with media and public perceptions about our industry “not being regulated by the FDA”, this less than above board practice of selling MOG as mushrooms draws potentially bad scrutiny to our craft. So far, despite recent industry pressure, the FDA and FTC have been slow in acting to clarify the issue.
Meanwhile packaging with mushroom images is ubiquitous while the supplement facts panels list terms like “cultured mycelia”, “mycelium biomass,” or “mycelia, spore, and fruiting body”, which hide the presence of grain, and you have the perfect conditions for Myco-Washing to thrive.
Did You Know?
In a study of 19 Reishi supplements sold in the US, only 5 (26%) were found to be authentic mushrooms. In a Consumer Labs review of Reishi products, the “bestselling” brand contained 0.6% beta glucans and 71% grain starch.
26%
of tested Reishi supplements were authentic mushrooms
71%
grain starch in the bestselling brand — with just 0.6% beta-glucans
How to Know What You’re Actually Buying
If you’re investing in authentic well-crafted functional mushroom supplements, here’s what to look for:
Fruiting body, clearly stated. The label should explicitly say “fruiting body” or “made from the fruiting body.” If it says “mycelium,” “full spectrum,” or simply “mushroom” without specifying, proceed with caution and dig deeper with the company.
Beta-glucan content listed. Look for a supplement facts panel that lists beta-glucan percentages or mg per serving — not just total polysaccharides. A quality lion’s mane or reishi extract should have meaningful, tested beta-glucan levels. (Specifically, β-(1,3/1,6)-glucans)
Starch content disclosed or low. Some reputable companies now test for and disclose alpha-glucan (starch) levels specifically to demonstrate the absence of significant grain content.
Certified organic. Organic certification adds a layer of third-party accountability that signals the manufacturer is invested in product integrity.
Transparent sourcing. Where were the mushrooms grown? On what substrate? Are there certificates of analysis available? Brands with nothing to hide tend to share this information openly.
The Bold Botanica Difference
Why Bold Botanica Does It Differently
At Bold Botanica, our three certified organic mushroom extract products are made exclusively from the fruiting bodies of organically grown mushrooms — the actual mushroom, as most humans and our ancestors have done for thousands of years. We don’t use myceliated grain. We don’t Myco-Wash our labels. We don’t cut corners with cheap filler substrate masquerading on labels as a “mushroom”. And we don’t believe in marketing a leprechaun riding a pink unicorn on a rainbow fantasy to consumers who are seeking and deserving of the real thing – true mushrooms.
We understand that functional mushrooms have legitimate, well-studied benefits when the right compounds are present in the right concentrations. But those benefits are almost 100% tied to the fruiting body of a mushroom — properly cultivated, properly extracted, properly tested mushroom material.
We source our organic mushroom extracts from Nammex, the industry leader in mushroom analysis and research. They have been working with mushroom growers in China for 40 years to produce premier organic mushroom extracts. At Bold Botanica we 3rd party lab test each extract and final product for purity and bio-active strength.
You’ve worked hard for your health and your money. You deserve to know exactly what you’re putting in your body — and what you’re actually paying for.
Bold Botanica is committed to transparency, quality, and the kind of education that empowers consumers to make genuinely informed choices. Have questions about our mushroom products or extraction methods? We welcome the conversation.
Alena Miles, Bold Botanica Co-Founder and Brand & Sustainable Sourcing Manager, has a diverse history in the natural products industry in marketing, global sourcing, product development, and her true passion, organic herb farming.
James “Slim” Miles – is a 30 year veteran of the natural products industry, Phytotherapist, Ayurvedic Practitioner, a co-founder of Bold Botanica, and VP of Innovation & Science at Employee Owned Apotheca, Inc.
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