The problem: every peptide website shows a Certificate of Analysis, and almost nobody reads one properly. A COA can look impressive and still tell you nothing about the vial in your hand. In ten minutes, this guide will teach you to read one like a quality-control chemist: what each section means, the five checks that matter, and the tricks sellers use to make a weak certificate look strong.
What a COA is (and is not)
A Certificate of Analysis is a lab report for one specific batch of a product. It lists the tests performed, the method used, the acceptance limits and the measured results. In regulated industries it is a legal quality document. In the research peptide market it is the only objective evidence you get that the powder is what the label says.
What a COA is not: a guarantee about every vial a company has ever sold, a marketing badge, or proof of anything if it does not match your lot number. A certificate from last year’s batch says nothing about this year’s.
Anatomy of a peptide COA
| Section | What it should say | Why it matters |
|---|---|---|
| Header | Testing lab name, address, report number, date | Lets you verify the lab exists and the report is real |
| Sample ID | Product name, lot / batch number | Must match the label on your vial |
| Appearance | e.g. “white lyophilized powder” (blue for copper peptides) | A quick sanity check |
| Purity (HPLC) | Percentage, with the chromatogram | How much of the sample is the target peptide |
| Identity (MS) | Expected vs observed mass, with the spectrum | Proves the peptide is the right molecule |
| Content / assay | Measured mg per vial | Catches under-filled vials |
| Signature | Analyst and reviewer | Accountability |
Reading the HPLC result
High-performance liquid chromatography pushes the dissolved sample through a column that separates molecules by how strongly they stick to it. A detector draws a chart: time on the horizontal axis, signal on the vertical axis. Each peak is a different substance.
- The main peak is your peptide. Its area, as a share of the total area of all peaks, is the purity figure.
- Small peaks are impurities: truncated sequences, deletion products, leftover synthesis reagents.
- What “good” looks like: one tall, sharp main peak and a flat baseline. Research grade is typically ≥98%.
The catch: HPLC tells you how pure a sample is, not what it is. A vial of the wrong peptide can still show 99% purity. That is why the next section matters more.
Reading the mass spectrometry result
Mass spectrometry (MS, or LC-MS when coupled to chromatography) weighs the molecules. Every peptide has a known molecular weight calculated from its sequence, so the test is simple: does the observed mass match the expected one?
- Look for an expected mass and an observed mass side by side. They should agree within about 1 Da for small peptides.
- Larger peptides often show several peaks for different charge states (for example [M+2H]²⁺, [M+3H]³⁺). These are normal and should all point back to the same molecular weight.
- No MS data at all? Then nothing on that certificate proves identity.
The 5-point COA checklist
- Lot match. The batch number on the COA matches the label on your vial.
- Independent lab. The report comes from a named third-party lab, not the manufacturer, and the lab exists when you search for it.
- Purity with a chromatogram. A number alone is not enough; the chart should be attached.
- Identity by MS. Observed mass matches the expected mass for that peptide.
- Recent date. The test date is consistent with the batch you received.
Want to see what a lot-matched certificate looks like? Browse the TrueLabs COA library.
7 tricks that make a weak COA look strong
- The forever COA. One certificate image reused for every batch for years.
- The universal COA. The same report layout and numbers across completely different peptides.
- The in-house COA. A certificate from the manufacturer that sold the powder, presented as independent testing.
- Purity without identity. A high HPLC number with no mass spectrometry.
- The cropped chromatogram. The chart is cut so impurity peaks fall outside the frame.
- The impossible number. “99.99%” purity on a cheap product. Real research-grade peptides are usually reported between 98% and 99.9%.
- No lab name. A certificate with a logo but no address, report number or analyst.
Expected masses for popular peptides
Use this table as a quick reference when checking an MS result.
| Compound | Expected molecular weight |
|---|---|
| BPC-157 | ~1419.5 Da |
| GHK (peptide only) | ~340.4 Da (~404 Da with copper) |
| Ipamorelin | ~711.9 Da |
| CJC-1295 with DAC | ~3647 Da |
| CJC-1295 without DAC (Mod GRF 1-29) | ~3368 Da |
| Semax | ~813.9 Da |
| Selank | ~751.9 Da |
| Epithalon | ~390.4 Da |
| KPV | ~342.4 Da |
| SS-31 | ~639.8 Da |
| MOTS-C | ~2174.6 Da |
| Tirzepatide | ~4813.5 Da |
| NAD+ | ~663.4 Da |
TB-500 is sold as several different fragments under the same name, so its expected mass depends on the exact sequence. That is exactly why an MS result matters for TB-500 in particular; see our TB-500 guide.
Frequently asked questions
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What does COA stand for?
Certificate of Analysis: a lab report showing the tests, methods and results for one specific batch of a product.
What purity should a research peptide have?
Research grade is usually 98% or higher by HPLC, with identity confirmed by mass spectrometry.
Is HPLC enough to verify a peptide?
No. HPLC measures purity, not identity. Mass spectrometry is needed to confirm the molecule is the right peptide.
How do I know a COA is real?
Check that it names an independent lab you can look up, includes a report number and date, attaches the chromatogram and mass spectrum, and matches the lot number on your vial.
Related reading
- How to spot fake or underdosed peptides
- How to choose a research peptide supplier in Canada
- How to store peptides
- BPC-157 vs TB-500
All TrueLabs products are sold for in vitro and laboratory research use only. They are not intended for human or veterinary use, and nothing in this article is medical advice.