04 Fruiting Body vs. Mycelium: The Truth About Mushroom Supplements Most Brands Don't Talk About

By BloomRenew Wellness Team | May 2026 | 7 min read

Fungi have a life cycle that's fundamentally different from plants, though the distinction is often misunderstood.

Mycelium is the fungal root network — a web of thread-like filaments called hyphae that grow underground or through a substrate like wood or grain. It's the living, feeding part of the organism. Think of it as the root system of a plant.

The fruiting body is the above-ground mushroom we're all familiar with — the cap, stem, and gills. It's the reproductive structure that the fungus produces to spread spores. Think of it as the fruit of the plant.

Here's what matters most: the bioactive compounds that make medicinal mushrooms therapeutically valuable are concentrated predominantly in the fruiting body.

Specifically, beta-glucans — the immunomodulatory polysaccharides that are the most studied functional compounds — are found at much higher concentrations in the fruiting body. Hericenones, the NGF-stimulating compounds in Lion's Mane, are found exclusively in the fruiting body. Triterpenes, the compounds in Reishi responsible for stress-adaptogenic effects, are predominantly located in the fruiting body.

The Mycelium-on-Grain Problem

Most commercial mycelium-based mushroom products follow a two-step production process. First, mycelium is inoculated onto a grain substrate — typically brown rice or oats. Then, the grain-mycelium mass is dried and ground into powder.

The problem is straightforward: the final product still contains a large amount of grain starch. Because there's no economically viable way to fully separate the mycelium from the substrate it grew on, what you're actually buying is a mixture — and often mostly grain.

Research published in Frontiers in Microbiology found that many mycelium-on-grain products contained alpha-glucans (starch) as the predominant polysaccharide, not beta-glucans. Some samples had beta-glucan content as low as 1–5% of dry weight.

Quality fruiting body extracts, by contrast, typically contain 20–40% beta-glucans by dry weight.

This difference is not minor. It's the difference between receiving a functional dose of the compounds that research is actually built on, versus purchasing a product that is largely grain powder with some mushroom material mixed in.

How to Spot the Difference on a Label

Supplement labels can be deliberately ambiguous, so knowing what to look for is essential.

Generic terms like "mushroom" or "mushroom powder" could refer to either fruiting body or mycelium — you'll need to look further. Labels that say "mycelium" or "myceliated grain" indicate mycelium-on-grain products with likely high grain content. The phrase "fruiting body extract" is what you're looking for — it indicates concentration from the actual mushroom.

"Full spectrum" often means both mycelium and fruiting body are included, but this requires beta-glucan content verification to assess quality. The most reliable marker is a direct statement of beta-glucan percentage — anything above 20% suggests quality fruiting body extraction.

Organic certification ensures the growing substrate wasn't contaminated with synthetic pesticides and is more meaningful for fruiting body products.

The most transparent brands list their beta-glucan content directly on the label. If a brand doesn't disclose this number, that's worth asking about.

Why This Matters More for Some Mushrooms Than Others

The fruiting body versus mycelium distinction carries different weight depending on the mushroom species.

For Lion's Mane, hericenones — the compounds studied for NGF stimulation — are found only in the fruiting body. A mycelium-based Lion's Mane product provides none of the primary cognitive-support compound.

With Reishi, the most studied triterpenes (ganoderic acids) are concentrated in the fruiting body, particularly in the outer skin. Reishi skin extract is actually considered premium for this reason.

Turkey Tail research is built on fruiting body extracts. The PSK and PSP compounds studied in clinical research came from fruiting body extracts, and most significant Turkey Tail research was conducted with pharmaceutical-grade fruiting body material.

Chaga is somewhat different — it's a sclerotium (a hardened fungal mass) rather than a true fruiting body, and its bioactive compounds are distributed throughout the structure. Quality and sourcing still matter significantly, however.

The Certification Factor

Organic certification matters more for mushrooms than for many other supplements, and for a specific reason.

Mushrooms are hyperaccumulators — they readily absorb heavy metals, pesticides, and other contaminants from their growing environment. While this property makes them ecologically useful for fungal bioremediation, it also means that non-organic mushrooms grown in contaminated substrates can concentrate those contaminants significantly.

This is particularly relevant for Chaga, which grows on birch trees that may be in polluted environments. It applies to Reishi, often grown on logs that may have been chemically treated. And it's important for any mushroom grown in Asia, where heavy metal contamination in agricultural areas is more common.

Organic certification provides assurance that the growing substrate was free of synthetic pesticides and that heavy metal testing is part of the production standard.

What BloomRenew Uses

BloomRenew Mushroom Coffee uses organic fruiting body mushrooms for all six functional mushrooms in its formula. The product is manufactured in an NSF-certified, GMP-certified facility with BRCGS certification — a food safety standard that requires documented testing of raw materials, including mushroom extracts.

This means the beta-glucan content is real, not a grain starch substitute. It's the reason the product costs more than random mushroom powders — and why the functional difference is noticeable.

The Bottom Line

Not all mushroom supplements are created equal. The label on the front almost always looks similar. What's inside is often very different.

If you're going to invest in functional mushrooms — whether in coffee, capsules, or tinctures — ask one critical question: is this fruiting body, and what's the beta-glucan content?

If you can't get a straight answer, that tells you something important about the brand's commitment to transparency.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any new supplement, especially if you are pregnant, nursing, taking medications, or have a medical condition.

References: Blagodatski A et al., Front Microbiol, 2018 | Wasser SP, Appl Microbiol Biotechnol, 2002 | Hobbs CR, in Medicinal Mushrooms: An Exploration of Tradition, Healing & Culture, 2003