Reading a COA
A certificate of analysis is a lab's report on one sample from one batch. The certificate below is fictional, and the numbered notes under it explain each part.
Last reviewed . About this date
| Fictional sample. Not a real certificate. | |||
|---|---|---|---|
| 1Lab | Example Analytical, lab.example | ||
| 2Accreditation | Certificate SAMPLE-0000 | ||
| Client | Example Vendor | ||
| 3Product as labeled | Retatrutide, 10 mg per vial | ||
| 4Lot or batch | SAMPLE-LOT-000 | ||
| 5Dates | Sample received 2026-01-05. Report issued 2026-01-12. | ||
| 6Report number | EX-0000-SAMPLE | ||
| Test | Method | Limit | Result |
| 7Identity | LC-MS (mass spec) | Mass matches the expected mass | Matches |
| 8Purity | HPLC-UV | 98.0% or higher | 98.6% |
| 9Amount in vial | HPLC against a reference standard | 90% to 110% of label | 9.7 mg (97%) |
| 10Endotoxin | LAL test | Stated on report | Below limit |
| 11Sterility | None | None | Not tested |
| 12Sign-off | The approver's name and title, with the date | ||
The numbered parts
- Lab. The testing lab’s name and a way to reach it. You need both to confirm the report yourself.
- Accreditation. A certificate number proves nothing until you find it in the accreditor’s directory with these tests on the lab’s scope (A2LA FAQ).
- Product as labeled. The peptide and amount the vendor claims. The tests further down should back up both.
- Lot or batch. This should match the lot printed on your vial. ICH Q7 says a certificate should name the batch it covers (ICH Q7).
- Dates. The day the lab received the sample and the day it issued the report. An old report may not describe what’s shipping today.
- Report number. Use it to confirm the report through the lab’s own website.
- Identity. The test that shows the vial holds the peptide on the label. Look for mass spectrometry, written as MS or LC-MS. ICH Q6A says a retention time on its own isn’t specific enough (ICH Q6A).
- Purity. The share of the material that is the target peptide, usually measured by HPLC. Chemists measure identity separately from impurities and content (McCarthy et al., 2023), so a high purity number doesn’t settle identity.
- Amount in vial. The amount of peptide the lab found, compared with the label. In a 2024 study of semaglutide bought online, the vials held 28.56% to 38.69% more than their labels said (Ashraf et al., 2024b).
- Endotoxin. Toxins from bacteria, which need their own test under USP chapter 85 (USP <85>). That 2024 study found endotoxin in every vial it tested (Ashraf et al., 2024b). A blank here means nobody checked.
- Sterility. A separate test that takes at least 14 days and covers only the units tested (USP <71>). The sample leaves it blank, and a real COA may too.
- Sign-off. ICH Q7 calls for a dated signature from an authorized quality person (ICH Q7). The sample shows a placeholder on purpose, so nobody can reuse it as a template.
Signs of a faked or stretched COA
- The lab can’t confirm it. You found the lab yourself, sent the report number, and the lab has no record of it, or its copy shows different results.
- The same report covers different products. Identical results or report numbers across several products or batches mean at least some of those COAs are copies.
- The lab is the vendor. Writing in The Conversation, a McMaster University professor said “third-party” labs behind vendor COAs are often the vendors themselves (Phillips, 2026).
- “Aligned” instead of “accredited.” A lab can call itself ISO 17025 aligned or compliant without holding accreditation. A2LA and IAS list the false claims they’ve caught (A2LA directory) (IAS).
- Purity and nothing else. No identity result and no endotoxin result leaves the two biggest questions open (ICH Q6A).
- Signs of editing. Mismatched fonts, blurry numbers, or text boxes laid over the original. A clean PDF proves nothing either, which is why the lab lookup matters more than the file.
The limit of any COA
Even a genuine COA describes one sample. It can’t show that your vial is sterile, holds the labeled dose, or came from the tested batch. For that, see testing your own vial.
Sources for this page
- Frequently Asked Questions
A2LA says a scope of accreditation lists the specific tests a lab was found competent to perform, and capabilities not listed on the scope are not covered by its accreditation.
- Q7 Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients Guidance for Industry
ICH Q7 says a COA should list product name, batch, release and expiry or retest dates, each test's limits and numerical results, a dated quality signature, and the original maker's contact details.
- Specifications: Test Procedures and Acceptance Criteria for New Drug Substances and New Drug Products: Chemical Substances Q6A
ICH Q6A says identification solely by a single chromatographic retention time is not specific, and the guideline does not adequately cover higher molecular weight peptides.
- Reference Standards to Support Quality of Synthetic Peptide Therapeutics
The authors write that peptide identity is typically confirmed with several orthogonal methods, including HPLC retention time, NMR, and mass spectrometry, separate from impurity and content tests.
- Multifactor Quality and Safety Analysis of Semaglutide Products Sold by Online Sellers Without a Prescription: Market Surveillance, Content Analysis, and Product Purchase Evaluation Study
Of 317 online pharmacy links, 134 led to 59 illegal sites; test vials were 7.7% to 14.37% pure, held 28.56% to 38.69% more semaglutide than labeled, and all had endotoxin.
- <85> Bacterial Endotoxins
USP says the Pharmacopeial Discussion Group approved the <85> Bacterial Endotoxins Test as a harmonized standard, official in USP since December 1, 2012.
- <71> Sterility Tests
The 2008 harmonized USP <71> text says its tests are not by themselves designed to ensure a batch is sterile, a pass covers only the sample examined, and incubation lasts at least 14 days.
- The peptide problem: Hype is outrunning the evidence
McMaster professor Stuart Phillips writes that the "third-party" labs issuing peptide purity certificates are often the vendors themselves, linking to a CBC Radio explainer.
- Search A2LA Directory of Accredited Organizations
A2LA's directory searches accredited organizations by name, certificate number, scope, or test method and links to suspended, withdrawn, and inactive certificates and false accreditation claims.
- False Claims of Accreditation
IAS names organizations that misuse its accreditation mark, including one issuing IAS-marked certificates without ever being accredited, and asks users to check its directory.