COA Verification Guide
WIKI · QUALITY & TESTING · READ BEFORE BUYING ANYTHING
A Certificate of Analysis (COA) is a lab report tying a specific batch of product to measured identity and purity. On The GLP Lounge, an unverified COA counts for nothing — verification means checking the document with the lab that issued it.
≥99%HPLC purity benchmark
±0.5 DaMass-spec identity window
2Labs the community trusts
0Excuses for no batch number
The verification workflow
- Get the batch/lot number printed on your vial — not just the vendor's listing.
- Match it to the COA. Batch number, compound, fill mass and test date must all line up.
- Verify with the lab directly. Janoshik prints a verification code on every report — enter it at janoshik.com. PeptideMeter results are publicly indexed. A COA that can't be verified at the source is decoration.
- Check the purity figure. HPLC purity ≥99% is the community benchmark for GLP-1 analogues; be suspicious below 98%.
- Check identity. Mass spectrometry should match the theoretical mass (semaglutide ≈ 4113.6 Da, tirzepatide ≈ 4813.5 Da) within tolerance.
- Confirm quantity. Good reports state measured content per vial (e.g., "10.4 mg") — underfilled vials are the most common quality failure in community testing.
Reading a report
| Field | Example | What it tells you |
|---|
| Sample / compound | Tirzepatide, lyophilized | Identity claimed by the sender |
| Batch № | TZ-2606-B2 | Must match your vial exactly |
| HPLC purity | 99.31% | Fraction of peptide content that is the target molecule |
| MS observed mass | 4813.7 Da | Confirms the molecule is what it claims to be |
| Quantity | 10.21 mg/vial | Actual fill vs label claim |
| Verification code | JAN-XXXXXX | Lets you confirm the document with the lab |
Red flags
- COA image with the batch number cropped, blurred or edited.
- Purity shown but no quantity — underdosing hides here.
- "Lab tested" claims naming labs that don't exist or won't verify.
- The same COA reused across multiple batches or months.
- Vendor refuses third-party testing of a customer-submitted sample.
Community testing results and lab methodology debates live in COA & Analytical Testing. Confirmed failures get posted to Buyer Beware.
Rule of thumb: the vendor's COA gets you interested; an independent, verifiable test of your batch gets you confidence.