How to Read a Mushroom Extract Certificate of Analysis (COA): A B2B Buyer’s Guide

Introduction: Why COAs Matter More Than Most Buyers Realise

If you are sourcing functional mushroom extracts for your supplement brand, you have almost certainly received a certificate of analysis from a supplier. You may have even glanced at it, noted that the numbers looked reasonable, and moved on to pricing discussions.

That is a mistake.

The COA is the only document that connects what a supplier claims about their product to what is actually in the powder. Without it, you are buying on trust. And in the functional mushroom industry — where raw material quality varies enormously and adulteration is not uncommon — trust without verification is a liability.

The problem is that most B2B buyers do not know how to read a COA critically. They see a table of numbers and assume the document speaks for itself. It does not. A COA can tell you a great deal about product quality, testing rigour, and supplier credibility — but only if you know what to look for, what the numbers actually mean, and which red flags should make you walk away.

This guide is designed to make you that buyer. We will walk through every section of a mushroom extract COA, explain what each test measures and why it matters, and give you the specific questions to ask your supplier before committing to a purchase.

What Is a Certificate of Analysis (and What It Is Not)

A certificate of analysis is a document issued by a laboratory — either the supplier’s own facility or an independent third-party lab — confirming the test results for a specific batch of material. For a mushroom extract, a properly constructed COA should include:

• Product identification (species, part used, extraction method)
• Batch or lot number
• Date of manufacture and date of testing
• Specifications (the targets the product is expected to meet)
• Actual test results (what the laboratory measured)
• Testing methodology for each parameter
• Heavy metals and microbial safety panels
• The name and accreditation of the testing laboratory

What a COA is not: a general quality statement, a product brochure, or a document that applies to all batches of a product indefinitely. A COA is batch-specific. If your supplier sends you a COA dated eighteen months ago for a product you are ordering today, that document is meaningless for the batch you will receive. Always ask for the COA matching the specific lot number of your shipment.

The Anatomy of a Mushroom Extract COA

A complete COA for a functional mushroom extract will contain several distinct sections. Here is what each one means and what to check.

Product Identification

The top of the COA should clearly state:

• Species name — both the common name and the Latin binomial. For example, “Lion’s Mane (Hericium erinaceus)” or “Reishi (Ganoderma lucidum).” If a COA lists only a common name with no Latin binomial, that is a concern — it suggests a lack of rigour in species identification.
• Part used — fruiting body, mycelium, or a blend. This matters enormously. Fruiting body extracts and mycelium-based products have very different bioactive profiles. All extracts supplied by FunctionalMushrooms.eu are from fruiting body, except Cordyceps CS-4, which is a mycelium product produced via submerged fermentation — a fundamentally different process from mycelium-on-grain.
• Batch or lot number — a unique identifier tying this COA to a specific production run. No batch number means no traceability. This alone should be a deal-breaker.
• Extraction method — hot water, ethanol, or dual extraction. This should match what the supplier has told you about the product. A dual-extracted Reishi, for instance, should show both water and ethanol extraction on the COA.

Specifications vs Results

Most COAs present two columns side by side: the specification (what the product should contain) and the result (what the lab actually measured). This comparison is the core of the document.

What to look for:

• Results should meet or exceed specifications. If a spec says “beta-glucans ≥30%” and the result says 28%, the batch has failed its own standard — even if 28% is still a decent number in absolute terms.
• Results that exactly match specifications on every parameter are suspicious. Analytical chemistry produces variability. A COA where every result lands precisely on the target number is either fabricated or the specifications have been written after the fact to match the results.
• Pay attention to units. Beta-glucan content expressed as a percentage of dry weight is standard. If units are missing or inconsistent, ask for clarification.

Beta-Glucan Testing Methods

This is the section that separates buyers who understand mushroom quality from those who do not. The testing method used to measure beta-glucans is as important as the result itself.

There are two primary approaches:

Enzymatic method (Megazyme K-YBGL): This is the correct method. The Megazyme assay uses a series of enzymatic reactions to first remove starch and then specifically quantify (1,3)- and (1,6)-beta-D-glucans — the bioactive compounds responsible for the immunomodulatory properties of medicinal mushrooms. It gives you a genuine beta-glucan number.

Gravimetric (or UV spectrophotometric) method: This method measures total polysaccharides—a category that includes beta-glucans, starch, chitin, alpha-glucans, and other inactive sugars. A mushroom extract can test at 60% “polysaccharides” using this method, yet contain only 15% actual beta-glucans. The remainder is filler that contributes nothing to product efficacy.

This distinction is not academic. It is the single most common way that low-quality extracts are made to look premium on paper. If a COA lists “polysaccharides” as the primary quality metric rather than beta-glucans, or if it uses a gravimetric method without specifying the Megazyme assay, treat the numbers with extreme caution. For a detailed explanation of why this matters, read our guide on why polysaccharides and extraction ratios are not reliable quality markers.

Active Marker Compounds

Beyond beta-glucans, specific mushroom species have their own marker compounds that indicate extract quality. A comprehensive COA should test for these where applicable:

• Lion’s Mane: Hericenones (>0.5%) — these are the compounds most closely associated with nerve growth factor (NGF) support. They are alcohol-soluble, which is why a dual-extracted Lion’s Mane is more valuable than a simple hot water extract.
• Reishi: Ganoderic acids (1%) — triterpenes that contribute to Reishi’s adaptogenic properties. Also alcohol-soluble and only present in meaningful quantities in dual-extracted products.
• Cordyceps CS-4: Cordycepin (>1.5%) and adenosine (>0.5%) — the key bioactive nucleosides. Cordyceps Militaris also targets high cordycepin content.

A COA that only reports beta-glucans without species-specific markers is incomplete. It tells you the extract contains mushroom polysaccharides, but it does not confirm the presence of the compounds that make each species unique and commercially valuable.

Heavy Metals Panel

Mushrooms are natural bioaccumulators — they absorb metals from their growing substrate and environment. This is a biological reality, not a quality flaw, but it means heavy metals testing is non-negotiable for any extract entering the EU market.

A COA should test for and report the following, with results within EU limits set by Commission Regulation 2023/915:

A COA that omits the heavy metals panel entirely — or that only tests for one or two metals — is incomplete. All four metals should be tested on every batch. If your supplier’s COA does not include arsenic or mercury, ask why. There is no good reason to omit them.

Microbiological Panel

The microbiological panel confirms that the extract is safe for human consumption from a food safety standpoint. Standard parameters include:

• Total plate count (TPC) — total aerobic mesophilic bacteria. Typically specified at <10,000 CFU/g for food-grade extracts.
• Yeasts and moulds — specified at <100 CFU/g or <1,000 CFU/g depending on the standard applied.
• Coliforms — an indicator of sanitary conditions during processing. Should be <100 CFU/g or negative.
• E. coli — must be absent (negative per gram tested).
• Salmonella — must be absent (negative per 25g tested).

Missing microbial results are a serious omission. If a supplier provides a COA with beta-glucan numbers but no microbial panel, the document is fundamentally incomplete — it tells you about potency but says nothing about safety.

Pesticide Residues

Pesticide residue testing screens for a panel of chemical pesticides that may be present from the cultivation environment. For organic-certified extracts, pesticide residues should be below the limits of detection. For conventional (non-organic) extracts, results should fall within EU Maximum Residue Limits (MRLs).

If you are sourcing a product that will carry organic claims, the pesticide panel on the COA is one of the documents your certifying body may request during an audit. Make sure it is there.

Red Flags: Five Warning Signs of a Questionable COA

After reviewing hundreds of COAs from suppliers across the industry, these are the patterns that consistently signal a document that should not be trusted at face value.

1. No Batch or Lot Number

A COA without a batch number cannot be traced to a specific production run. It might be a generic document, a template, or a result from a single batch that the supplier applies to all subsequent shipments. Without a batch number, you have no way to confirm that the COA relates to the material you are actually purchasing. This is the most basic requirement — and the most common omission.

2. “In-House” Testing Only

A COA issued exclusively by the supplier’s own laboratory, with no independent verification, is a conflict of interest. The entity selling the product is also the entity certifying its quality. This does not mean in-house results are automatically fabricated — many suppliers have competent internal labs. But without independent confirmation from an ISO 17025-accredited third-party laboratory, the COA carries less weight.

At FunctionalMushrooms.eu, we dual-test every batch at both Eurofins and Alkemist Labs — two independent, internationally accredited laboratories with no commercial relationship to our business. This removes any ambiguity about the numbers.

3. Suspiciously Round Numbers

Analytical chemistry produces results with decimal precision. A beta-glucan result of 35.7% is realistic. A result of exactly 35.0% is possible but less common. A COA where every single parameter lands on a perfectly round number — 35% beta-glucans, 1.0% ganoderic acids, 0.0 ppm mercury — suggests the numbers have been chosen rather than measured.

4. “Polysaccharides” Instead of Beta-Glucans

This is the most commercially significant red flag. If a COA’s primary quality metric is “total polysaccharides” rather than “beta-glucans (enzymatic method),” the document is almost certainly overstating the extract’s bioactive content. Polysaccharides include starch, chitin, and other inactive compounds. A 60% polysaccharide number can easily correspond to only 15-20% actual beta-glucans. Any supplier that leads with polysaccharide content either does not understand mushroom chemistry or is deliberately obscuring product quality.

5. Missing Heavy Metals or Microbial Results

A COA that reports only the flattering numbers (high beta-glucans, high marker compounds) while omitting the safety parameters (heavy metals, microbiology) is telling you something. It is telling you either that those tests were not performed, or that the results were not favourable. Neither explanation is acceptable for a product entering the EU food supplement supply chain.

Third-Party vs In-House Testing: Why Independent Labs Matter

The difference between a supplier-generated COA and an independently verified COA is the difference between a claim and evidence.

In-house testing has a role. Suppliers use it for routine quality control during production — checking that each batch is within specification before release. There is nothing wrong with this. But when it comes to commercial documentation shared with B2B buyers, in-house results should be supported by independent verification.

Independent third-party laboratories operate under ISO 17025 accreditation — the international standard for testing and calibration laboratories. This accreditation requires documented quality management systems, proficiency testing, measurement traceability, and regular audits by an accreditation body. It is the assurance that the laboratory is competent, impartial, and producing reliable results.

Two laboratories that represent the gold standard for mushroom extract testing are:

• Eurofins — one of the world’s largest networks of food, environment, and pharmaceutical testing laboratories. ISO 17025 accredited across multiple methods relevant to botanical extracts.
• Alkemist Labs — a US-based laboratory specialising in botanical identity and potency testing, with extensive experience in mushroom extract analysis. Also ISO 17025 accredited.

FunctionalMushrooms.eu conducts dual testing on every batch at both laboratories. This is not standard industry practice — most suppliers rely on a single lab or in-house testing alone. We do it because the data should be airtight. When a buyer asks to see our COA, the conversation ends with confidence, not with more questions.

What to Ask Your Supplier Before You Buy

Armed with an understanding of what a COA should contain and what the numbers mean, here are the specific questions to put to any mushroom extract supplier before you place an order.

Can I see a recent COA for this specific batch?

Not a generic COA. Not a COA from six months ago. The COA for the batch you will receive. If the supplier cannot provide this — or says the batch has not been tested yet — ask when testing will be completed and request the COA before you confirm the order.

Which laboratory performed the testing?

You want a named, accredited laboratory. If the answer is “our in-house lab” with no independent verification, that is a data point. If the answer is an ISO 17025-accredited third-party lab, ask for the lab’s accreditation number to verify it.

What testing method was used for beta-glucans?

The correct answer is the Megazyme enzymatic method (K-YBGL). If the supplier says “UV spectrophotometry,” “gravimetric method,” or simply “polysaccharide testing,” they are not measuring beta-glucans — they are measuring a broader category that inflates the numbers. This is the single most important technical question you can ask about a mushroom extract COA.

Are heavy metals tested per EU Regulation 2023/915?

This confirms that the supplier is testing specifically against EU food safety limits, not a different standard. The EU limits for food supplements are: lead <3.0 ppm, mercury <0.1 ppm, cadmium <1.0 ppm, and arsenic <2.0 ppm. If the supplier is testing against different limits — or not testing for all four metals — ask why.

Do you test for species-specific marker compounds?

For Lion’s Mane, you want hericenones quantified. For Reishi, ganoderic acids. For Cordyceps, cordycepin and adenosine. A supplier that only tests for beta-glucans is providing a generic quality metric. Species-specific markers confirm that the extract delivers the full profile of compounds that make that particular mushroom valuable. If your supplier does not test for these markers, consider whether you are getting the full picture of what you are paying for.

Can you explain any results that are outside specification?

Natural variation exists in biological products. A batch that measures 33% beta-glucans against a 35% specification is not necessarily cause for alarm — but the supplier should be able to explain it, document the deviation, and tell you how it affects the commercial suitability of the batch. Transparency here is a strong indicator of a trustworthy supplier.

A Note on Extraction Ratios

You may encounter COAs or product specifications that quote a DER (drug-to-extract ratio) — for example, “10:1 extract” or “20:1 concentrate.” At FunctionalMushrooms.eu, we do not quote extraction ratios. Here is why: a DER is not a verifiable method of measuring quality. It tells you how much raw material went in relative to extract produced, but it says nothing about what the extract actually contains. A 10:1 extract with 15% beta-glucans is objectively less potent than a 5:1 extract with 35% beta-glucans.

We focus on what can be measured, verified, and independently confirmed — species-specific quality markers tested by accredited laboratories. The COA is where that verification lives, not an extraction ratio on a product label. For more on this topic, see our detailed article on why extraction ratios and polysaccharides are not reliable quality markers.

Conclusion

A certificate of analysis is not paperwork. It is the document that tells you whether the product you are buying is what the supplier says it is. Learning to read a COA critically — checking the testing method, verifying the lab, matching the batch number, and looking for the red flags outlined above — is one of the most commercially valuable skills a B2B mushroom extract buyer can develop.

The buyers who get this right build brands on real quality, supported by data. The buyers who skip this step build brands on assumptions — and assumptions get exposed eventually.

If you are evaluating mushroom extract suppliers and want to see what a properly documented COA looks like, we are happy to share ours. Every batch we supply is dual-tested at Eurofins and Alkemist Labs, with full COAs available on request. No NDA required, no questions about why you want to see the data.

For more on EU regulatory compliance for functional mushrooms, or to discuss your specific requirements, the best next step is a conversation.