2026-08-19 · Testing · 6 min read

How to read a certificate of analysis

In short: a trustworthy COA names an accredited laboratory, ties to a specific batch and lot, states the analytical method and its detection limit, and reports numbers — not just "PASS." The most common tricks are summary badges with no data, "not detected" at a detection limit too high to matter, and testing inputs instead of the finished product.

Brands have learned that "lab tested" sells. So the certificate of analysis — once an internal quality document — is now marketing collateral. Some published COAs are exactly what they appear to be. Others are theater. Here's how to tell which one you're holding.

1. Who did the testing?

The first question is whether the document comes from an independent, accredited laboratory or from the brand itself. Look for the laboratory's name, address, and an ISO/IEC 17025 accreditation — the international standard for testing-lab competence. A COA generated by the manufacturer's in-house lab isn't worthless, but it isn't independent, and a "COA" with no laboratory identified at all is a graphic, not a certificate.

2. What exactly was tested?

A meaningful COA is batch-specific: it identifies the product, the lot number, and the date the sample was received and analyzed. Check whether the lot on the certificate matches the lot in your hand — a two-year-old COA for a different batch tells you about the past, not your tub. The subtler version of this trick is testing the raw ingredient rather than the finished product. Metals arrive from multiple ingredients; only a finished-product test captures what you actually consume.

3. What method, and what detection limit?

For heavy metals, the workhorse method is ICP-MS (inductively coupled plasma mass spectrometry), typically under validated AOAC methods, and it can see parts-per-billion. The number to hunt for is the detection limit (LOD/LOQ). "Not detected" is only as good as the limit it's measured against: ND at a limit of 0.005 ppm is informative; ND at 0.5 ppm can conceal an exposure many times California's daily safe harbor once you multiply by a 35-gram serving. If a certificate says ND but doesn't state the limit, it is withholding the only number that gives ND meaning.

4. Numbers, or adjectives?

A real result is a quantity: micrograms per gram, parts per billion, with units. Be suspicious of documents that report only "PASS," "COMPLIANT," or a checkmark against unstated criteria. Pass against what threshold? Set by whom? The whole value of a COA is that it lets you do the arithmetic yourself: concentration × serving size = daily exposure, compared against a published limit. A document that hides the concentration is asking you to outsource exactly the judgment it claims to enable.

5. Does the math survive the serving size?

This is the step almost nobody does, and it's the one that matters. Concentrations are reported per gram; you consume servings. A powder at 0.02 µg of lead per gram sounds tiny — at a 35-gram serving it's 0.7 µg/day, above California's 0.5 µg/day reproductive safe harbor for lead. Every time we publish a finding, this multiplication is shown in full. When you read anyone's COA — including ours — insist on seeing it.

What we publish

Our standard is simple: the laboratory's own certificate, in full, with the accreditation visible, the lot number matching the purchase records, the method and detection limits stated, and the exposure arithmetic laid out next to it. If a document we publish ever fails the checklist above, hold us to it — the checklist is the point.