How to Spot a Good Certificate of Analysis (CoA) vs. a Bad One—for Supplements
If you rely on your contract manufacturer to “handle the testing,” this one’s for you. CoAs (certificates of analysis) are not all created equal—some prove your product is safe, compliant, and on-spec; others quietly expose you to retailer rejection, FDA scrutiny, and lawsuits. Here’s how to tell the difference—and what to fix before your next run.
Key takeaways
Finished-product testing matters. “Verified via raw material” or “in-process checks” ≠ testing the final lot that ships.
Numbers, not just “PASS.” Retailers and regulators expect numeric results tied to a batch/lot, with named methods and an accredited lab.
Heavy metals need limits. “Report only” isn’t a spec. You need pass/fail limits and results with a clear basis(ppm, µg/g, per serving).
Micro specs must fit your matrix. Loose limits protect factories, not brands. Set justified targets tied to your product and ingredients.
Your CoA reflects your spec. Weak specs → weak CoAs. Build the spec first (identity, purity, strength, composition), then test to it.
What a strong CoA includes
Product identifiers: product name, batch/lot number, manufacture date, packaging type.
Methodology: the specific method (USP/AOAC/validated HPLC/ICP-MS), not vague “in-process” language.
Accredited lab: ISO/IEC 17025 (or equivalent) named on the CoA.
Numeric results with units & basis: e.g., Vitamin D: 12.1 µg/serving (spec ≥10 µg/serving; HPLC-UV).
Pass/fail criteria for every parameter: identity, label-claim actives, heavy metals with limits (Pb, Cd, Hg, As), micro (TPC/yeast & mold/pathogens), claim-specific tests (e.g., gluten <20 ppm), allergens where relevant.
Authorized sign-off: analyst/QC approval, date, page count.
Red flags of a weak CoA
Asterisks and footnotes instead of data (e.g., “verified via raw material”). Translation: no finished-product test.
“PASS” without a value. Not acceptable for Amazon, Whole Foods, CVS—or FDA.
Heavy metals listed as “report.” With no limits or basis, results are meaningless.
Ambiguous units/basis. “1.76 µg” of what—per capsule, per gram, per serving?
Overly loose micro limits (e.g., TPC ≤ 50,000 CFU/g on a product that routinely achieves ≤ 5,000).
Missing retailer asks: no lab accreditation, no method references, no batch/lot.
CoA upgrade checklist (give this to your co-man)
Lock the finished-product specification first. Cover identity, strength/label claim, purity (metals, residual solvents if applicable), micro, composition, organoleptics, and any claim-dependent tests (gluten-free, sugar-free, etc.).
Define testing per lot. What’s every lot vs. qualified by component (only when scientifically justified per 21 CFR 111.75)? Document the rationale.
Name the methods. Tie each spec to USP/AOAC or validated in-house methods (keep a brief validation summary on file).
Require numeric results. Every parameter shows a number with units and basis, plus pass/fail.
Set heavy-metal limits + basis. Specify ppm or µg/g and provide per-serving conversions if you make per-serving claims.
Tighten micro limits to your matrix. Use achievable, justified targets that deter “dirty” runs.
Use an ISO 17025 lab and list it on the CoA.
Add traceability. Batch/lot, sample plan (e.g., beginning/middle/end pulls), who released it.
Build retailer-ready versions. Pre-format CoAs that meet Amazon/retailer checklists.
Don’t hide behind asterisks. If component testing replaces finished testing for a specific analyte, cite 21 CFR 111.75, show supplier qualification and in-process controls—and still finish-test where feasible.
Quick example: weak → strong
Weak: Vitamin A—Spec ≥300 µg RAE; Method: “in-process checks”; Result: PASS.
Strong: Vitamin A (RAE)—Spec ≥300 µg/serving; Result 342 µg/serving; Method HPLC-UV (USP adaptation); Lab ISO 17025; Sample plan triplicate composite across run.
Summary
Your CoA is your brand’s evidence. If it doesn’t show what was tested, how, where, by whom, and exactly how muchwas found—gatekeepers won’t trust it. Start with a solid spec, insist on numeric finished-product results, and align formats to retailer requirements before your next lot.
Next steps (pick what fits you)
For founders/new brands
Signature 1-on-1 Consultation: Bring your current CoA/spec (or none). We’ll map your testing plan, tighten limits, align with Amazon/retailer expectations, and give you the exact asks for your co-man so your next CoA clears gatekeepers.
For founders who want structured learning
SSET: Supplement Startup Essentials Training: Learn which regs apply, how to build a market brief, how to find & vet co-mans, and how to set specs/read CoAs so you’re not flying blind.
For established brands (already in market)
CoA & Specification Tune-Up: Contact us to see how we can support you with spec rebuilds, CoA format upgrades (ISO-lab, numeric results, method calls), Amazon/retailer compliance packets, and supplier verification—so you reduce rejections and expand smoothly.