What a COA Actually Documents
A Certificate of Analysis (COA) is a lab report tied to a specific manufactured batch. At minimum, a proper one covers three things: the compound's identity (confirming the substance is what it claims to be), its purity as measured by a named analytical method — almost always HPLC (High-Performance Liquid Chromatography) for peptides — and the batch or lot number the report applies to.
A useful COA will also state the testing date and, ideally, the name of the laboratory that carried out the analysis. Without those two details, there's no way to verify when the testing happened or who's standing behind the result.
What "Purity" on a COA Actually Means
This is the part most people skim past. When a COA reports "≥99% purity" via HPLC, it means that when the sample was run through the chromatography column, roughly 99% of the detected peak area corresponded to the target compound rather than related impurities or byproducts.
That's a measure of chromatographic purity — not automatically proof of the exact quantity of compound in a given vial.
Those are related but genuinely different things. Purity tells you how clean the sample is relative to itself. It doesn't, on its own, confirm that a 10mg-labelled vial contains precisely 10mg — that's a separate measurement (quantification), and not every COA includes it. If a supplier is treating "purity" and "exact dose confirmed" as interchangeable, that's worth noticing.
What a COA Doesn't Tell You
- It doesn't confirm how the product was stored between testing and reaching you. A compound can test perfectly on the day of manufacture and still degrade if it's mishandled afterward.
- It's only as credible as the lab issuing it. An in-house or unnamed lab report carries less weight than one from an independent, named laboratory — anyone can put a percentage on a page.
- It applies to a specific batch, not the product in general. A COA for batch #1 doesn't tell you anything definitive about batch #4 unless the supplier is testing every batch, not just the first one they ever made.
Questions Worth Asking Any Supplier
Before trusting a COA — from us or anyone else — a few questions are worth asking directly:
- Is this COA from an independent third-party lab, or produced in-house?
- Does the batch number on the certificate match the batch number on the product you actually received?
- Is a COA provided for every batch, or just a representative one shown on the website?
- Can you get a copy before you order, not just after?