How to read a Certificate of Analysis (COA)
The five things to check on every COA before trusting a vendor.
Why a COA matters
A Certificate of Analysis is the single most important document a vendor can publish. It is the bridge between a marketing claim — '99% pure BPC-157' — and an independent, lab-verified fact. Without one, every claim is just text on a website.
The five things to check
1) The lab's name and accreditation (ISO 17025 is the gold standard). 2) A batch or lot number that matches what you ordered. 3) Mass-spec purity, not just HPLC area-percent. 4) Identity confirmation — does the molecular weight match the labeled compound? 5) The date — a COA from 18 months ago is not evidence about today's batch.
Red flags
No lab name, no batch number, screenshots instead of PDFs, identical COAs across multiple batches, or 'in-house testing' presented as third-party verification. Any of these should drop a vendor's trust score in your head immediately.
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