Quality Guide · Updated March 2026
How to Read a COA for Mushroom Supplements
A Certificate of Analysis is the only proof that a mushroom supplement actually contains what the label says. Here's exactly what to look for — and what red flags mean.
Board-Certified Physician · Medical Reviewer · Published February 11, 2026
What Is a COA?
A Certificate of Analysis (COA) is a document issued by an independent analytical laboratory that verifies the composition, purity, and safety of a supplement product. It's the only independent verification that a brand's label claims are accurate.
Why This Matters for Mushrooms Specifically
The mushroom supplement industry has a documented quality problem. A 2017 analysis by the Usefully Mushrooms research group found that many products claiming to contain "medicinal mushrooms" were primarily composed of grain starch from myceliated substrates — with negligible actual mushroom content. Without a COA, you have no way to know if you're paying for mushrooms or oats.
✓ What a COA Confirms
- • Mushroom species identity (DNA verification)
- • Beta-glucan content (actual bioactive compounds)
- • Heavy metals below safety limits
- • No harmful pesticides or mycotoxins
- • Microbial safety (no E. coli, Salmonella)
✗ What a COA Doesn't Guarantee
- • Clinical efficacy for specific health claims
- • Bioavailability (how much absorbs)
- • Efficacy of extraction method
- • Consistency across all future batches
- • Results if the COA is outdated (>2 years)
The 5 Key Sections to Check
Lab Accreditation
The lab issuing the COA must be an independent, accredited third party — not the brand's own internal lab. Look for ISO/IEC 17025 accreditation or state-licensed analytical lab credentials in the footer of the document.
🚩 Red Flag: COA issued by "Brand Name Quality Control Lab" — that's an in-house lab, not third-party.
Identity / Species Verification
The COA should confirm that the mushroom species claimed (e.g., Hericium erinaceus for Lion's Mane) are actually present. The gold standard is ITS (Internal Transcribed Spacer) DNA barcoding which can identify species at the molecular level.
Look for: "Identity — PASS" and the Latin binomial species name in the test results.
Beta-Glucan Content
This is the most important number for immune and health benefits. A quality fruiting body extract should show 15–40% beta-glucans by dry weight. Products with myceliated grain biomass often show <5% beta-glucans and >40% starch.
| Beta-Glucan % | What It Means | Quality |
|---|---|---|
| 25–40% | Premium fruiting body extract | Excellent |
| 15–25% | Good quality extract | Good |
| 5–15% | Mixed fruiting body/mycelium | Marginal |
| <5% | Likely myceliated grain biomass | Poor |
Heavy Metals Panel
Mushrooms are bioaccumulators — they absorb heavy metals from their growing substrate. A complete panel should test for Lead (Pb), Mercury (Hg), Arsenic (As), and Cadmium (Cd). Results should fall below USP <232> limits.
Lead
≤10 ppm
Mercury
≤3 ppm
Arsenic
≤15 ppm
Cadmium
≤5 ppm
Lot Number & Date
Match the lot number on the COA to the lot number printed on your bottle or packaging. A COA for a different batch doesn't verify your product. Check the analysis date — COAs older than 2 years may not reflect current production quality.
💡 Tip: Email the brand asking for the COA for the specific lot number on your package. A legitimate brand will respond within 24–48 hours.
Beta-Glucans vs Polysaccharides: Not the Same Thing
⚠️ Common Misleading Claim
Many supplement labels say "high in polysaccharides" or show "polysaccharide %" on a COA. This is misleading. Starch is a polysaccharide. Myceliated grain biomass (the cheap filler) is extremely high in starch polysaccharides — which have no immune benefit. Only beta-glucan polysaccharides (specifically beta-1,3/1,6-glucans from mushroom cell walls) deliver the benefits you want.
✓ BETA-GLUCANS
- • Found in mushroom cell walls (chitin matrix)
- • Binds to dectin-1 receptors on immune cells
- • Activates NK cells, macrophages
- • Acts as prebiotic for gut microbiome
- • What COA should specifically test for
✗ STARCH POLYSACCHARIDES
- • From grain (rice, oats, barley substrate)
- • Digested as a simple carbohydrate
- • No immune modulating effects
- • Common in myceliated grain biomass
- • Often shown as high "polysaccharide %" on inferior COAs
COA Red Flags at a Glance
COA tests only "total polysaccharides" — not beta-glucans specifically
This is the most common sleight of hand in the industry. Always ask for beta-glucan-specific results.
High starch content (>15%) alongside high "polysaccharides"
Real mushroom fruiting bodies have very low starch. High starch = myceliated grain in the mix.
COA dated more than 2 years ago
Production quality can change. An old COA doesn't represent current batches.
Brand refuses to share COA or says it's "proprietary"
Lab test results aren't a trade secret. If a brand won't share their COA, that tells you everything.
No heavy metals panel in the COA
Mushrooms bioaccumulate heavy metals from soil and substrate. A COA without heavy metals testing is incomplete.
Trusted Testing Labs for Mushroom Supplements
Eurofins
ISO/IEC 17025 Accredited
The world's largest food and supplement testing network. Gold standard for identity testing and contaminant screening. Multiple facilities worldwide.
Alkemist Labs
ISO/IEC 17025 Accredited
Specialized in botanical identity testing. Excellent for mushroom species DNA verification and TLC/HPTLC fingerprinting of extracts.
NSF International
Third-Party Certification Body
NSF Certified for Sport certification means athletes can trust the product is free from banned substances and accurately labeled.
Intertek
ISO/IEC 17025 Accredited
Full-service testing including pesticide residue, mycotoxins, microbiological safety, and active compound quantification.
Frequently Asked Questions
What is a COA and why do I need to check it for mushroom supplements?
A Certificate of Analysis (COA) is a document from an independent third-party laboratory confirming what's actually in a supplement — and what isn't. Without a COA, any claim on a mushroom supplement label is unverified. A COA should confirm: (1) the mushroom species claimed are present at the stated amount, (2) beta-glucan content is real (not just starch), (3) the product is free from heavy metals like lead, mercury, arsenic, and cadmium, (4) no harmful microbes or pesticides are present.
What beta-glucan percentage should a good mushroom extract have?
A high-quality fruiting body hot water extract should contain 15–40% beta-glucans by dry weight. Anything below 10% is a red flag — it likely contains significant starch from myceliated grain. The best products (like Real Mushrooms) advertise >25% beta-glucans and publish COA results to prove it. Note: 'polysaccharides' on a label is NOT the same as beta-glucans — some starch is also a polysaccharide but has no immune benefit.
Can I trust a COA on a brand's own website?
Partially. A COA on a brand's website is better than nothing, but ideally you want to verify: (1) the lab that issued the COA is a real accredited third-party lab (not an in-house lab), (2) the COA includes a lot number that matches the batch you're buying, (3) the COA is dated within the last 12–24 months. Use ISO/IEC 17025 accredited labs as the gold standard — they must meet international standards for test accuracy.