What is a certificate of analysis (COA) for compounded medications?
A certificate of analysis reports the identity, potency and sterility of a specific batch. Here is how to read a COA and why it matters for compounded medications.
June 27, 2026 · 5 min read · For everyone
When a compounded medication arrives, the label states a strength. A certificate of analysis is the document that shows the label is true for the exact batch in your hands.
For peptides, hormones and GLP-1 preparations, a COA is the clearest signal that a pharmacy tests what it makes. This guide explains what a COA contains, how to read one, and why it should travel with every order.
What is a certificate of analysis?
A certificate of analysis (COA) is a document that reports laboratory testing results for a specific batch of a preparation. For compounded medications it typically confirms identity, potency and, for injectables, sterility and endotoxin, so the strength and purity on the label match what is actually in the vial.
A COA is batch-specific. It is tied to a single lot, not to the product in general, which is what makes it meaningful: it describes the exact preparation you received rather than a manufacturer’s typical result.
What does a COA test for?
A COA for a compounded injectable generally reports identity, potency, sterility and bacterial endotoxin. Identity confirms the ingredient is what the label says, potency confirms the strength, sterility confirms the absence of viable microbes, and endotoxin testing checks for contaminants that sterilization alone would not remove.
- Identity: confirmed by HPLC against a reference standard.
- Potency: a quantitative assay verifies the labeled strength.
- Sterility and endotoxin: required for injectable preparations.
- Beyond-use date: set from real stability data, not a default.
How do you read a certificate of analysis?
Check that the lot number on the COA matches your vial, that each test lists a specification and a result within it, and that the date is current. Identity and potency should show a pass against a stated range, and injectables should include a sterility result. If a lot cannot produce a COA, treat that as a gap.
You do not need to be a chemist to use a COA. The practical test is simple: does the document exist, does it match your lot, and does every listed result fall inside its specification. A pharmacy that releases on proof can answer all three.
Why a COA matters for compounded medications
Without a COA, a provider prescribes and a patient injects on faith that the label is accurate. A COA replaces that trust with evidence for the specific lot, which is why a careful pharmacy tests every batch and ships the certificate with the order rather than filing it away.
Compounded preparations are made in smaller, patient-specific batches, so per-batch testing is exactly where quality is proven or lost. The COA is the record that makes the quality visible before a single dose is given.
Frequently asked questions
Does every compounded medication come with a COA?
It should, but it depends on the pharmacy. Careful 503A pharmacies test each batch and release it with a certificate of analysis. If a pharmacy cannot provide a COA for your lot, that is a reason to ask why.
What is the difference between a COA and a label?
A label states the intended strength; a COA is the test result proving the batch meets it. The label is the claim, the COA is the evidence for the specific lot you received.
What does HPLC mean on a COA?
HPLC (high-performance liquid chromatography) is a laboratory method used to confirm the identity and measure the potency of an ingredient by comparing it against a known reference standard.
Can I request a COA for my prescription?
Yes. Providers and patients can ask the pharmacy for the certificate of analysis tied to their lot. A pharmacy that tests every batch can produce it on request.
What is a certificate of analysis (COA) for compounded medications?
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