What Is a COA and Why Does It Matter?\n\nA Certificate of Analysis (COA) is a document issued by a laboratory that reports the test results for a specific batch of peptide. It is not a marketing claim — it is analytical data.\n\nFor EU-based researchers, a COA answers one critical question: does this peptide meet the purity level the vendor claims?\n\nNo COA means no verification. Every reputable vendor provides one. If a supplier can't or won't produce one, that is a decision you can make right there.\n\n## The Five Sections of a COA\n\n### 1. Product Identification (Name, Sequence, Molecular Weight)\n\nThe first section identifies what was tested.\n\nWhat to check:\n\n- Peptide name and sequence — Confirm the amino acid sequence matches what you ordered. Even small sequence errors can change the compound entirely.\n- Molecular weight (MW) — The theoretical MW should match the observed MW from mass spectrometry. A mismatch here is a serious red flag.\n- Form — Free peptide, acetate salt, or hydrochloride salt? The salt form affects molecular weight and solubility. Know which form you're ordering.\n\n### 2. Batch / Lot Number and Manufacturing Date\n\nEvery COA should reference a specific production batch.\n\nWhy lot numbers matter: A vendor may have tested one batch that was excellent, but shipped you a different batch with different results. The COA is only valid for the batch it references.\n\n### 3. HPLC Purity Analysis\n\nHigh-Performance Liquid Chromatography (HPLC) separates the peptide from impurities and measures its purity percentage.\n\n| Parameter | What It Tells You |\n|---|---|\n| Purity % | ≥95% is research-grade minimum. ≥98% is preferred. |\n| Chromatogram | A clean chromatogram has one dominant peak. Multiple large peaks mean impurities. |\n| Retention time | Consistent with the expected compound's retention time. |\n\n### 4. Mass Spectrometry (MS)\n\nMass spec confirms the molecular identity of the peptide — not just its purity, but that it is actually the compound you ordered.\n\nCommon theoretical masses (monoisotopic, protonated):\n- BPC-157: ~1,419.6 Da\n- TB-500: ~2,223.1 Da\n- CJC-1295: ~3,647.1 Da\n\n### 5. Additional Assays\n\n| Test | What It Measures | Acceptable Range |\n|---|---|---|\n| Karl Fischer (KF) | Water content | ≤5% for most peptides |\n| Amino Acid Analysis | Correct amino acid composition | Matches expected sequence |\n| Endotoxin Testing | Bacterial contamination | <5 EU/mL for injectables |\n\n### 6. Laboratory Identification\n\nWho ran the test matters as much as what they found. Third-party labs with ISO 17025 accreditation are the gold standard. In-house testing is common but less independent.\n\n## Red Flags Checklist\n\n- [ ] COA is available (no COA = no deal)\n- [ ] Lot number on COA matches what you'll receive\n- [ ] Analysis date is within 12 months\n- [ ] HPLC purity ≥95% (≥98% preferred)\n- [ ] Chromatogram is included (not just a percentage)\n- [ ] Mass spec confirms correct molecular weight\n- [ ] Lab is identified\n- [ ] Third-party testing where possible\n\n## FAQ\n\nShould I accept an in-house COA? In-house testing is common and not automatically unreliable. Prefer third-party where available.\n\nWhat purity level do I need for research? For in vitro: ≥95% is acceptable. For animal studies: ≥98% is preferred. Below 90% introduces too much impurity variance.\n\nCan I request the raw HPLC/MS data? Yes. Contact the lab using the contact info on the COA and reference the sample ID.