Beta-Glucans: What Are They and Why Do They Matter?

THE BOXED-IN MYCELIUM INDEX

Field Guide No. 004 • Mushroom Science

Introduction

If you've researched mushroom supplements, you've probably seen the term beta-glucans used as a measure of quality. Many companies highlight beta-glucan percentages, while others criticize products that contain too little. But what exactly are beta-glucans, and why are they important?

Beta-glucans are naturally occurring polysaccharides found in the cell walls of fungi, including medicinal mushrooms.

They are one of the major structural components that help give fungal cells their strength and shape.

Because beta-glucans are found naturally in mushrooms, they are often discussed when comparing mushroom powders, extracts, and tinctures. However, understanding what a beta-glucan number actually represents requires a little context.

In this Field Guide, we'll explain what beta-glucans are, where they come from, how they're measured, and why they are only one part of evaluating a quality mushroom product.

What Are Beta-Glucans?

Beta-glucans are complex carbohydrates made from glucose molecules linked together in specific patterns. In mushrooms, they are an important part of the fungal cell wall, where they provide structural support and help maintain the integrity of the cells.

Not all beta-glucans are the same. The beta-glucans found in fungi differ structurally from those found in oats, barley, or yeast. Mushroom beta-glucans typically contain β-(1→3) backbones with β-(1→6) branching, giving them characteristics distinct from cereal beta-glucans.

Because they are natural components of mushroom tissue, beta-glucans are often measured when evaluating mushroom ingredients. However, the percentage alone does not tell the whole story about a product's quality or how it was produced.

Where Do Beta-Glucans Come From?

Beta-glucans are produced naturally as mushrooms grow. They become part of the fungal cell wall in both the mycelium and the fruiting body, although the amount and composition can vary depending on the mushroom species, stage of growth, and growing conditions.

Different medicinal mushrooms naturally contain different levels of beta-glucans. For that reason, it isn't scientifically accurate to expect every mushroom species to have the same beta-glucan percentage.

Processing also matters. Drying, grinding, extraction methods, and the final formulation can all influence the measured concentration of beta-glucans in a finished mushroom product.

Understanding these factors helps explain why comparing products based on a single percentage can be misleading.

Why Do Companies Measure Beta-Glucans?

Measuring beta-glucans helps estimate the amount of fungal polysaccharides present in a mushroom ingredient. Because beta-glucans are naturally found in mushroom cell walls, they are often used as one indicator of mushroom content and product consistency.

However, a beta-glucan value should be interpreted carefully. It does not measure every beneficial compound in a mushroom, and it does not automatically indicate the quality of an extraction process.

Beta-glucan testing is most useful when considered alongside other information, such as the mushroom species, whether the product uses fruiting bodies or mycelium, the extraction method, and the manufacturer's transparency about sourcing and processing.

In other words, beta-glucans are an important piece of the puzzle, but they are not the whole picture.

How Are Beta-Glucans Measured?

Laboratories commonly measure beta-glucans using validated analytical methods, such as the AOAC enzymatic method, which is designed to distinguish beta-glucans from other carbohydrates, including alpha-glucans such as starch.

This distinction is important because mushrooms naturally contain multiple types of carbohydrates. A reliable test helps identify how much of the carbohydrate content consists specifically of fungal beta-glucans.

The results are usually reported as a percentage of dry weight. That percentage can be useful when comparing similar products, but it should always be interpreted alongside information about the mushroom species, extraction method, and overall product formulation.

A trustworthy manufacturer should be willing to explain how the testing was performed and what the reported numbers actually represent.

Are Higher Beta-Glucan Percentages Always Better?

Not necessarily. A higher beta-glucan percentage can indicate a greater concentration of fungal beta-glucans, but that number should never be viewed in isolation.

Different mushroom species naturally vary in their chemistry. Extraction methods, moisture content, formulation, and the type of product being tested can all influence the reported percentage.

A single laboratory value also does not tell you whether the mushroom was properly identified, how it was grown, how it was extracted, or whether other naturally occurring mushroom compounds are present.

The most useful approach is to look at beta-glucan results alongside the complete picture—the species, fungal material used, extraction method, testing, and the manufacturer's transparency.

What Should Consumers Look For?

Beta-glucan numbers are useful, but they should be considered as part of a broader evaluation of a mushroom product.

When comparing products, look for:

• The mushroom species used

• Whether the product contains fruiting bodies, mycelium, or both

• The extraction method used

• Independent testing, when available

• Clear labeling and transparent manufacturing information

• Beta-glucan results that are explained in context, not simply used as a marketing claim

A trustworthy company should help you understand what the numbers mean, rather than expecting you to assume that a single percentage tells the entire story.

Field Notes

Beta-glucans deserve their reputation as an important component of medicinal mushrooms—but they are not the only measure of quality.

A meaningful evaluation considers the entire story: the mushroom species, the fungal material used, the extraction method, the analytical testing, and the manufacturer's willingness to explain the results.

At Boxed-In, we believe that numbers should educate, not confuse. Beta-glucan testing is valuable when it's presented honestly and in the proper scientific context.

An informed customer should understand what the number measures, what it doesn't measure, and why context always matters.

Continue Exploring the Mycelium Index

Understanding beta-glucans is one step toward understanding how mushroom products are made and evaluated.

The Boxed-In Mycelium Index is an expanding collection of Field Guides covering fungal biology, cultivation, extraction methods, analytical testing, and the science behind medicinal mushrooms.

Continue exploring the Field Guides to learn how mushrooms are grown, extracted, tested, and transformed into high-quality tinctures.

Selected References

McCleary, B. V., & Draga, A. (2016). Measurement of β-Glucan in Mushrooms and Mycelial Products. Journal of AOAC International, 99(2), 364–373.

Rop, O., Mlcek, J., & Jurikova, T. (2009). Beta-Glucans in Higher Fungi and Their Health Effects. Nutrition Reviews.

Vetvicka, V., & Vetvickova, J. (2014). β-Glucan Improves Conditions of Chronic Fatigue in Mice by Stimulation of Immunity. Open Biochemistry Journal.

Ruthes, A. C., Smiderle, F. R., & Iacomini, M. (2015). Mushroom Heteropolysaccharides: A Review on Their Sources, Structure and Biological Effects. Carbohydrate Polymers.