TL;DR — A Certificate of Analysis ties a batch to lab test results proving purity and identity. Here's how to read one — HPLC, mass spec, endotoxin, matching lot — and how to spot a faked or reused COA.
For Research Use Only · 21+ · not for human or veterinary use · not medical advice.
A Certificate of Analysis (COA) is the single most important document in research-compound sourcing. It is a lab's report on what a specific batch actually contains — and learning to read one is the difference between researching with a known quantity and gambling on a mystery powder.
What a COA proves
A legitimate COA ties a specific batch / lot number to test results from an analytical lab. If the lot number on your vial doesn't match the COA, the document is meaningless — always check this first.
The three tests that matter
- HPLC purity — measures how much of the sample is the target compound. Look for ≥98–99%.
- Mass spectrometry (MS / LC-MS) — confirms molecular weight and identity, proving the vial holds the compound it claims and not a cheaper substitute.
- Endotoxin (LAL) — critical for anything intended for injectable research. Look for <0.5–1 EU/mg.
Verify the lab, not just the paper
The most trusted third-party lab in this space is Janoshik Analytical, which maintains a public database (public.janoshik.com) where you can enter a task number and key to confirm a report is real. MZ Biolabs and Colmaric are also recognized. A COA from an unnamed “in-house” lab proves nothing.
Red flags
- Generic COA with no lab name or contact
- Old dates, or one reused PDF across every product
- Only a purity percentage — no chromatograms or MS data
- A vendor who refuses to share the full report
The gold standard: test it yourself
On a first order from any new vendor, the disciplined move is to send a sample to Janoshik yourself (~$200–300). It is the only way to be certain.
This is exactly the work LabGrade does for you — every vendor in our directory is rated against third-party COA evidence. See our methodology, or unlock our verified sources.