How to Read a Mushroom Extract COA (2026): What the Numbers Actually Mean

A Certificate of Analysis, or COA, is the single most useful document a mushroom extract brand can hand you. It is the lab’s report on what is actually inside the bottle. The problem is that most shoppers have never been shown how to read one, so a COA becomes a trust badge that gets waved around rather than checked. This guide walks through every section of a real mushroom extract COA and shows you which numbers matter, which ones are marketing, and which missing tests should make you put the product down.

We review extracts using the same six criteria on every brand, and the COA is where four of those six get verified. If a brand cannot or will not show you one, that is the review.

What a COA is, and what it is not

A COA is a lab result for a specific batch of product. Good ones name the accredited lab, list a batch or lot number, and give a test date. That batch number matters more than people realize. A COA for last year’s batch tells you nothing about the bottle on the shelf today, and some brands reuse an old flattering result across every batch.

A COA is not the same as a “third-party tested” claim on a label. Any brand can print those three words. The COA is the proof behind them, or the absence of proof when you ask and nothing arrives.

The identity test: are you even buying the right mushroom

The first thing a real COA establishes is identity. For Reishi that means confirming the material is Ganoderma lucidum, and for Lion’s Mane that it is Hericium erinaceus. This sounds basic, but adulteration and mislabeling are common enough in the mushroom supplement category that identity testing is not a formality.

Look for a stated method such as HPTLC or DNA-based identification. A COA that lists an active compound but never confirms the species is skipping the foundation.

Beta-glucan: the number brands hope you misread

Here is where most of the confusion lives. Many labels advertise a big “polysaccharides” percentage. Polysaccharides is a broad bucket that includes starches and added grain. When a mushroom extract is grown on grain and not properly separated, that leftover starch inflates the polysaccharide number and makes a weak product look strong.

Beta-glucan is the more meaningful measurement. It is the specific fraction associated with the fungal cell wall, and it is harder to fake because the test method used by good labs distinguishes true beta-glucan from alpha-glucan starch.

So the practical rule when you compare two COAs:

• A high “polysaccharide” percentage with no beta-glucan number is a soft signal at best.
• A specific beta-glucan percentage, measured by an enzymatic assay, is the number worth comparing across brands.
• A product where beta-glucan is far lower than the advertised polysaccharide figure is usually carrying grain filler.

We do not publish a single “correct” beta-glucan threshold, because the right target depends on the mushroom and the extract type. What we do is compare like against like, and we treat the presence of a real beta-glucan assay as a baseline for being taken seriously.

Triterpenes and the Reishi bitterness question

For Reishi specifically, triterpenes are the second family worth looking for. These are the bitter compounds, and they are fat-associated rather than water-associated, which is why extraction method changes what ends up in the bottle. Not every COA reports triterpenes, and the testing is less standardized than beta-glucan, so treat a triterpene number as a bonus data point rather than a pass or fail on its own.

The safety panel: heavy metals and contaminants

Mushrooms are efficient at pulling minerals out of their growing substrate, and that includes heavy metals. A serious COA reports levels for arsenic, cadmium, lead, and mercury, and it reports them against a limit so you can see the result is under threshold rather than just present.

Alongside metals, look for microbial testing, total yeast and mold, and ideally a pesticide screen. These are the tests that cost money and add nothing to a marketing claim, which is exactly why the cheapest brands quietly leave them off. A COA that reports active compounds but shows no safety panel is telling you where the brand spent its lab budget.

Extraction method: reading between the lines

The COA rarely states the extraction method outright, but it hints at it. A water-only extract will show cell-wall compounds like beta-glucan and very little in the way of triterpenes. A dual extraction, which uses both water and alcohol steps, is what captures both the water-associated and the fat-associated compounds. If a Reishi product claims a full-spectrum benefit but its COA shows only polysaccharides and no triterpenes at all, the method and the claim do not line up.

The five-second checklist

When a brand sends you a COA, run this before you read anything else:

• Is there a named, accredited lab, not just a logo?
• Is there a batch or lot number, and a recent date?
• Is there a real beta-glucan number, not just “polysaccharides”?
• Is there a heavy-metal panel reported against limits?
• Does the extract method implied by the numbers match the marketing?

Miss one and you have a question to ask. Miss three and you have your answer.

Why we keep pushing on this

Independent testing has repeatedly found active compound levels in the mushroom supplement category running below label claims, and the gap almost always hides behind vague language rather than outright lies. “Third-party tested,” “full spectrum,” and a large polysaccharide number are the three phrases that most often paper over a thin product. A COA cuts through all of it, but only if you know which line to read. Now you do.

For how these numbers play out across specific products, see our Reishi and Lion’s Mane extract comparisons, where the COA is one of the six criteria we score every brand on.