Beta-Glucan Testing Guide for Mushroom Buyers

Q: Should I demand third-party testing from my mushroom supplier?

Yes. Independent testing from ISO 17025 accredited laboratories ensures accuracy and removes conflicts of interest. Reputable suppliers provide batch-specific Certificates of Analysis proactively rather than only on request.

Why Beta-Glucans Are the Gold Standard Quality Marker

If you are evaluating functional mushroom extracts for your brand, product line, or personal use, one metric matters more than any other: beta-glucan content. Not total polysaccharides. Not extract ratios. Beta-glucans.

Beta-glucans are polysaccharides composed of glucose units linked by beta-1,3 and beta-1,6 glycosidic bonds. This specific molecular structure is what gives functional mushrooms their most well-documented biological activity. While mushrooms contain hundreds of compounds, beta-glucans are the primary immunomodulatory fraction and the most extensively studied class of bioactive molecules in species such as Reishi, Lion’s Mane, Turkey Tail, and Cordyceps.

The mechanism is well understood. Beta-glucans bind to the Dectin-1 receptor on innate immune cells — macrophages, dendritic cells, and neutrophils. This triggers a cascade of immune responses, including enhanced phagocytosis, cytokine production, and natural killer cell activation. The Dectin-1 receptor is highly specific: it recognises the beta-1,3-glucan backbone. Starch, cellulose, and other polysaccharides do not activate this pathway.

This is precisely why metrics such as “total polysaccharides” or “extract ratio” (10:1, 15:1) are misleading. They tell you very little about what is actually in the product. A mushroom extract could contain 50% polysaccharides and still deliver negligible immune-modulating benefit if those polysaccharides are primarily starch or grain-derived carbohydrates. As we have written about extensively in our article on why polysaccharides and extract ratios are not reliable quality markers, the industry must move beyond these outdated indicators.

The Problem with “Polysaccharide” Testing

The word “polysaccharide” means “many sugars.” It is a vast chemical category that includes:

Beta-glucans — the immunologically active fraction
Starch (alpha-glucans) — nutritionally unremarkable grain carbohydrate
Cellulose — a structural plant fibre with no immune activity
Chitin — a structural component of fungal cell walls
Glycogen — an energy storage molecule

When a Certificate of Analysis reports “40% polysaccharides,” it indicates the total weight percentage of all carbohydrate polymers present. It does not distinguish between bioactive beta-glucans and inert starch.

This becomes especially problematic with mycelium-on-grain products. In these products, the fungal mycelium is grown on a grain substrate — typically rice, oats, or millet — and the entire mass, including the uncolonised grain, is ground into powder. The resulting product can contain 50 to 70 per cent residual grain starch by weight. A generic polysaccharide assay will count all of that starch.

Consider this scenario, which is far from hypothetical: a mycelium-on-grain product tests at 60% total polysaccharides. An uninformed buyer might interpret this as a premium, potent extract. However, when that same product is subjected to the Megazyme beta-glucan assay — which enzymatically removes starch before measuring — the actual beta-glucan content is revealed to be just 8%. The remaining 52% is grain starch, contributing nothing to the product’s functional claims.

The supplement industry has been slow to adopt beta-glucan-specific testing for several reasons: cost, lack of regulatory mandate in some markets, and, frankly, because vague polysaccharide numbers allow lower-quality products to appear competitive. For B2B buyers sourcing mushroom extracts, understanding this distinction is not optional — it is the foundation of informed procurement. If your supplier cannot provide beta-glucan-specific data, that is itself a significant red flag.

Testing Methods Compared

Not all analytical methods are created equal. Here is how the most common approaches to mushroom quality testing compare.

The Megazyme Beta-Glucan Assay (AOAC 995.16)

The Megazyme assay, based on the McCleary method, is the gold standard for quantifying beta-glucans in mushroom products. Developed by Dr Barry McCleary and validated by the Association of Official Analytical Chemists (AOAC), this enzymatic method systematically removes non-beta-glucan polysaccharides before measurement.

The process works in two stages. First, the sample is treated with a series of enzymes — alpha-amylase, amyloglucosidase, and pullulanase — that hydrolyse starch and other alpha-glucans into simple sugars, which are then washed away. What remains is the beta-glucan fraction. Second, the remaining beta-glucans are hydrolysed with specific enzymes, and the released glucose is quantified colourimetrically

This two-stage approach is critical. By first removing everything other than beta-glucans, the method provides a true measure of the bioactive fraction. The AOAC 995.16 designation means the method has been collaboratively validated across multiple laboratories for accuracy and reproducibility.

Any serious mushroom extract supplier should test using this method. If a supplier cannot tell you their beta-glucan content as measured by the Megazyme assay, you should question whether they truly understand the quality of what they are selling.

UV Spectroscopy

UV spectroscopy measures the absorption of ultraviolet light by a sample. It can detect the presence of polysaccharides in general, but it lacks the specificity to differentiate between beta-glucans, starch, and other carbohydrate polymers. While it is inexpensive and fast, it is unsuitable as a primary quality metric for functional mushroom extracts. It may have a role in rapid screening, but should never replace enzymatic assays for beta-glucan quantification.

Congo Red Method

The Congo Red dye method is a traditional approach that exploits the dye’s ability to bind to beta-glucan chains, producing a measurable colour shift. While it can confirm the presence of beta-glucans, it is at best semi-quantitative. The binding is influenced by the molecular weight and conformation of the glucan chains, meaning results can vary significantly between samples. It is not suitable for quantitative quality control in a commercial supplement context.

HPLC (High-Performance Liquid Chromatography)

HPLC is not used for beta-glucan testing. However, it is an essential complement to the Megazyme assay. HPLC enables precise quantification of species-specific bioactive compounds: triterpenes (ganoderic acids) in Reishi, hericenones and erinacines in Lion’s Mane, cordycepin and adenosine in Cordyceps. For a complete picture of quality, buyers should look for both Megazyme beta-glucan data and HPLC analysis of relevant secondary metabolites. Our Lion’s Mane quality markers guide covers this in greater detail.

Iodine Starch Test

The iodine starch test is a simple, inexpensive screening tool. When iodine solution is applied to a mushroom powder, a dark blue-black colour indicates the presence of significant starch — a clear sign of grain contamination or a mycelium-on-grain product. A genuine fruiting body extract will produce little to no colour change. While this test is not quantitative, it is remarkably effective as a first-pass screening tool. Any product that turns dark blue under iodine testing warrants further scrutiny.

What Beta-Glucan Levels Should You Expect?

Beta-glucan content varies significantly by species, growing conditions, extraction method, and product form. The following ranges represent what you should expect from a quality dual-extracted fruiting body product, tested via the Megazyme method:

Lion’s Mane (Hericium erinaceus): 25–35%. Quality extracts should consistently hit this range. A value below 20% suggests poor extraction or raw material quality. See our Lion’s Mane quality markers article for compound-specific benchmarks.
Reishi (Ganoderma lucidum): 30–50%. Reishi is one of the richest sources of beta-glucans when properly extracted. Triterpene content (measured via HPLC) is equally important for this species.
Cordyceps (Cordyceps militaris): 25–40%. Cordycepin and adenosine content should also be verified alongside beta-glucans.
Chaga (Inonotus obliquus): 20–35%. Chaga also contains betulinic acid and melanin, which require separate analysis.
Turkey Tail (Trametes versicolor): 30–50%. This species is particularly beta-glucan-rich, with PSK and PSP being the most extensively researched fractions.
ABM (Agaricus blazei Murrill): 25%+. ABM delivers reliable beta-glucan levels in the 25%+ range of any functional mushroom. Learn more in our ABM article.
Tremella (Tremella fuciformis): Variable. Tremella’s key polysaccharides are acidic heteropolysaccharides rather than classical beta-glucans, so direct comparison is less meaningful. Evaluate based on specific polysaccharide characterisation.
Maitake (Grifola frondosa): 30–50%. The D-fraction is the most researched beta-glucan complex in Maitake.
Shiitake (Lentinula edodes): 20–35%. Lentinan, a specific beta-1,3-glucan with beta-1,6 branches, is the primary bioactive of interest.

Red flags to watch for:

If a supplier claims beta-glucan content above 60%, proceed with caution. While not impossible, numbers this high may indicate a testing methodology issue, a different assay being used, or outright fabrication. Always ask which method was used and request the underlying lab report.

Equally concerning is a product that reports only the total polysaccharide content and provides no beta-glucan figure. In 2026, there is no legitimate reason for a professional mushroom extract supplier to omit beta-glucan data. Its absence is itself a quality signal — and not a positive one.

How to Read a Mushroom Extract COA (Certificate of Analysis)

A Certificate of Analysis is the single most important document in B2B mushroom extract procurement. It should be batch-specific, issued by an independent laboratory, and contain clear, verifiable data. Here is what to look for.

Essential fields:

Beta-glucan content (%): the primary quality metric. It should specify the testing method used (Megazyme/AOAC 995.16). If the COA only reports total polysaccharides, it is incomplete.
Species identification: The COA should confirm the species, ideally through DNA verification or organoleptic and microscopic analysis. Adulteration and substitution are real issues in the mushroom supply chain.
Extraction method: Hot water, ethanol, or dual extraction. The method affects which compounds are present in the final product. Our extraction guide explains why this matters.
Heavy metals panel: Lead, cadmium, mercury, and arsenic levels should be reported and within EU regulatory limits. Mushrooms are bioaccumulators — heavy metal testing is non-negotiable.
Microbial testing: Total plate count, yeast and mould, coliforms, E. coli, Salmonella. These are standard food safety parameters.

Nice-to-have fields:

Triterpene content (especially for Reishi)
Species-specific compound quantification via HPLC (hericenones, cordycepin, etc.)
Pesticide residue screening
Organic certification documentation

Red flags on COAs:

Missing beta-glucan data: As discussed, this is the single most important metric.
Suspiciously round numbers: A beta-glucan content of exactly “30.00%” across multiple batches suggests the data may not be from real testing.
Outdated testing dates: A COA from two years ago is not relevant to today’s batch. Demand current, batch-specific documentation.
No lab accreditation: The testing laboratory should hold ISO 17025 accreditation, which ensures competence and impartiality in testing and calibration.
Internal testing only: COAs generated by the manufacturer’s own lab, without third-party verification, should be treated with scepticism.

Questions B2B Buyers Should Ask Their Supplier

Whether you are sourcing mushroom extracts for a supplement line, a food and beverage product, or a cosmeceutical formulation, these ten questions will help you separate credible suppliers from those who cannot substantiate their claims. This checklist is also valuable when choosing a trustworthy functional mushroom supplier.

What is the beta-glucan content of this product? Not polysaccharide content — beta-glucan content, specifically. If the supplier cannot answer this question immediately, that tells you something important.
Which testing method do you use for beta-glucan quantification? The answer should be the Megazyme method (AOAC 995.16). If they reference UV spectroscopy or a generic polysaccharide assay, the data are not reliable.
Is this product made from the fruiting body or the mycelium? Fruiting body extracts generally deliver higher beta-glucan content and avoid the grain contamination issues associated with mycelium-on-grain products. Both have valid applications, but you need to know what you are buying.
Can you provide a batch-specific COA? Not a generic specification sheet — a COA linked to the specific batch you are purchasing. Every batch varies, and credible suppliers test every batch.
Which laboratory performs your testing? Is it ISO 17025 accredited? Third-party, accredited laboratory testing is the baseline standard. Internal testing alone is insufficient for professional procurement.
What extraction method is used? Hot water extraction targets beta-glucans. Ethanol extraction targets triterpenes and other alcohol-soluble compounds. Dual extraction captures both. The method should match your formulation goals.
What is the source material, and where does it originate? Is the raw material organic? What country does it come from? What are the growing conditions? Traceability matters for quality, regulatory compliance, and EU Novel Food requirements.
Do you test for heavy metals and microbial contamination? This should be standard practice. Ask for the specific parameters tested and the limits applied. EU requirements are stricter than those of many other markets.
Can you provide HPLC data for species-specific compounds? Beta-glucans are the baseline. For species like Reishi (triterpenes), Lion’s Mane (hericenones), or Cordyceps (cordycepin), HPLC data adds a critical layer of quality verification.
Are you GMP certified? Good Manufacturing Practice certification ensures consistent production standards, proper documentation, and regulatory compliance. For the European market, this is essential.

The Business Case for Quality Testing

Investing in rigorous beta-glucan testing and demanding the same from your suppliers is not merely a quality exercise — it is a business strategy.

Brand protection. A single product recall, a failed regulatory audit, or a viral social media post exposing poor quality can cause lasting damage. Verified beta-glucan content provides a defensible quality claim.

Consumer trust and repeat purchases. Consumers in the functional mushroom space are increasingly educated. They read labels, compare COAs, and share information in online communities. Products with verified, specific beta-glucan content build the trust that drives long-term brand loyalty.

Regulatory compliance. The European market has specific requirements under the Novel Food Regulation, and enforcement is increasing. Products with clear, verifiable quality data are better positioned for regulatory scrutiny. Our Novel Food guide covers the current regulatory landscape.

Premium positioning and margin improvement. Products that can demonstrate superior beta-glucan content command higher prices. Quality-verified extracts enable premium positioning that generic “polysaccharide” claims cannot support.

B2B buyer confidence. If you are a supplier, providing Megazyme-tested beta-glucan data, batch-specific COAs, and full transparency gives your buyers confidence. That confidence translates to larger orders, longer contracts, and referrals.

How FunctionalMushrooms.eu Approaches Testing

At FunctionalMushrooms.eu, beta-glucan testing is not an afterthought — it is central to everything we do.

Every batch of every product is tested via the Megazyme method (AOAC 995.16). We do not rely on total polysaccharide figures, and we do not accept generic specification sheets in place of real analytical data.

Our testing is performed by third-party laboratories holding ISO 17025 accreditation. This ensures independence, accuracy, and reproducibility of results. We make full COA data available to our wholesale partners as standard practice.

Beyond beta-glucans, we verify species-specific compounds via HPLC — triterpenes for Reishi, hericenones for Lion’s Mane, cordycepin for Cordyceps — because a complete quality picture requires more than a single metric. Every product undergoes heavy metals testing, microbial screening, and species identity verification.

All production follows GMP-certified protocols, and our products are sourced from certified organic operations with full traceability from cultivation to finished extract.

We believe that transparency is not a marketing advantage — it is a baseline responsibility. If you are sourcing functional mushroom extracts and have questions about testing, quality, or compliance, we welcome the conversation.

Frequently Asked Questions

What is the best method for testing beta-glucans in mushroom supplements?

The Megazyme enzymatic assay (AOAC Method 995.16) is the gold standard. It specifically measures beta-glucans by first removing starch and other non-bioactive polysaccharides through enzymatic hydrolysis, then quantifying the remaining beta-glucan fraction.

What beta-glucan percentage should I expect from quality mushroom extracts?

Quality fruiting body extracts typically contain 25–50% beta-glucans depending on species. ABM typically reaches 25%, Turkey Tail 30–50%, Reishi 30–50%, and Lion’s Mane 25–35%. Products below these ranges may indicate poor extraction or raw material quality.

Why is polysaccharide content misleading?

Total polysaccharides include starch, cellulose, and chitin — not just bioactive beta-glucans. Mycelium-on-grain products can show 60% polysaccharides while containing only 5–10% actual beta-glucans, because residual grain starch inflates the total polysaccharide figure.

How do I read a mushroom extract Certificate of Analysis?

Look for beta-glucan percentage tested via the Megazyme method, a heavy metals panel (Pb, Cd, As, Hg), microbial testing, species identification, and extraction method. Red flags include missing beta-glucan data, reporting only polysaccharide values, and the absence of third-party laboratory accreditation.

Should I demand third-party testing from my mushroom supplier?

Yes. Independent testing by ISO 17025-accredited laboratories ensures accuracy and removes conflicts of interest. Reputable suppliers provide batch-specific Certificates of Analysis proactively rather than only on request.

The Complete Beta-Glucan Testing Guide for Functional Mushroom Buyers