Last updated: May 2026
Summary: A section-by-section walkthrough of a realistic peptide Certificate of Analysis (COA) using a hypothetical BPC-157 batch as the example. Each section is annotated with what the values should look like, what they mean, and what to flag if they don’t match expectations. Use this as a reference when reviewing COAs from any peptide supplier — yours, ours, or anyone else’s.
Why this walkthrough exists
The COA guide covers the framework of how to read a peptide COA. This walkthrough is the practical companion — a worked example showing what each section actually contains, with the kind of annotations a senior procurement reviewer would write in the margins.
The example below describes a representative research-grade BPC-157 COA. Real COAs vary in format depending on the issuing lab; the analytical content should match this structure.
Section 1 — Header / identification block
Typical content:
- Product name: BPC-157
- Catalog number / SKU: BPC157-5MG-LYO
- Batch number: 2026-04-BPC157-A1247
- Manufacture date: 2026-04-12
- Analysis date: 2026-04-15
- Testing laboratory: [Named third-party analytical laboratory, e.g., “Janoshik Analytical s.r.o.”]
- Lab document ID: LAB-2026-04157
- Submitted by: [Manufacturer or supplier name]
What to verify: the batch number on the COA must match the batch number on the physical vial label. The named testing laboratory must be a real, verifiable analytical facility. A “third-party tested” label with no named lab is the single most common COA red flag.
Annotation: “Lab document ID lets you verify with the lab directly if needed. Manufacture-to-analysis gap of ~3 days is typical and indicates the QC step happens before release rather than batch-by-batch testing months later.”
Section 2 — Identity (mass spectrometry)
Typical content:
- Method: ESI-MS (Electrospray Ionization Mass Spectrometry)
- Theoretical [M+H]⁺: 1420.56
- Measured [M+H]⁺: 1420.51
- Mass error: 35 ppm
- Spectrum chart: [Annotated chart showing the primary peak at the expected m/z value]
- Conclusion: Identity confirmed
What to verify: the measured mass must be within typical instrument tolerance (low parts-per-million error). A “perfect zero” mass error is suspicious — real measurements have small error. The theoretical mass must match the published molecular weight for the target sequence (BPC-157: 1419.55 g/mol; with protonation [M+H]⁺ it’s 1420.56).
Annotation: “Mass error within 50 ppm is normal for ESI. The spectrum chart should show a dominant target peak with minimal secondary peaks — a busy spectrum with multiple major peaks indicates contamination or sequence variants.”
Section 3 — Purity (reverse-phase HPLC)
Typical content:
- Method: Reverse-phase HPLC, C18 column, gradient elution
- Solvent system: Water/acetonitrile + 0.1% TFA
- Detection: UV at 214 nm (peptide bond)
- Run time: 30 minutes
- Chromatogram: [Annotated chart showing peaks vs. retention time]
- Target peak retention time: 14.2 minutes
- Target peak area: 99.4% of total integrated area
- Largest impurity: 0.32% at retention time 12.8 minutes
- Sum of all impurities: 0.6%
- Conclusion: Purity 99.4% (≥99% specification met)
What to verify: the chromatogram should show a dominant target peak (≥99% area). Side peaks should be small and few. The integration should sum to 100%. The detection wavelength of 214 nm is standard for peptide analysis (detects the peptide bond directly).
Annotation: “A ‘99% purity’ claim with a busy chromatogram showing multiple 1-2% peaks is misleading — those would sum to >5% total impurity. Always look at the chromatogram itself, not just the headline number.”
Section 4 — Counterion content
Typical content:
- Counterion: Trifluoroacetate (TFA)
- TFA content: 12.4% w/w
- Net peptide content: 87.6% w/w
- Method: Ion chromatography or ¹⁹F-NMR
What to verify: the COA should explicitly document the counterion type. TFA is the most common salt form from standard SPPS purification. The “net peptide content” is the actual peptide weight in a vial labeled with total weight. A 5 mg vial of “BPC-157 TFA salt” with 12.4% TFA contains ~4.38 mg of actual peptide and ~0.62 mg of TFA.
Annotation: “For most research applications, the net-peptide-content number is the one that matters — that’s the actual quantity of target compound. If a supplier doesn’t disclose counterion content, you’re guessing about effective dose.”
Section 5 — Water content
Typical content:
- Method: Karl Fischer titration
- Water content: 2.8% w/w
- Specification: ≤5%
- Conclusion: Within specification
What to verify: water content should be below 5% for properly lyophilized peptides. Higher water content indicates incomplete lyophilization, which can reduce stability and shelf life.
Annotation: “Water content rarely matters operationally unless it’s anomalously high — but it’s a quick check on lyophilization quality and a signal that the manufacturer is running the full QC battery.”
Section 6 — Endotoxin testing (when included)
Typical content:
- Method: LAL (Limulus Amebocyte Lysate) gel-clot or kinetic chromogenic
- Result: <0.25 EU/mg
- Specification: <1 EU/mg (typical low-endotoxin research-grade specification)
- Conclusion: Within specification
What to verify: endotoxin testing is not always included on standard COAs. If your research application requires low-endotoxin material (typical for in-vivo research models), confirm LAL was run and the result meets your specification before purchase.
Annotation: “If endotoxin matters for your research application, request LAL up front. Standard COAs without LAL aren’t necessarily worse, but they’re not directly comparable to ones with LAL.”
Section 7 — Conclusion / sign-off
Typical content:
- Overall conclusion: “This batch meets all specifications for research-grade BPC-157.”
- Analyst name: [Named analyst with role and credentials]
- Analyst signature: [Physical or digital signature]
- Lab director countersignature: [Where applicable]
- Date of release: 2026-04-15
What to verify: the COA should have a named, qualified analyst signature. An unsigned COA or a COA signed by “Quality Department” with no individual name is a weaker document.
What a complete COA review looks like in practice
A complete review takes 5–10 minutes per COA. The key checks in order:
- Batch number on COA matches the physical vial label
- Named testing lab is a real, verifiable facility
- Mass spectrometry confirms identity (mass error within typical range)
- HPLC purity ≥99% with a clean chromatogram
- Counterion content documented
- Water content within spec
- Endotoxin testing if your application requires it
- Analyst signature present
Any of these failing is grounds for declining the batch or escalating to the supplier.
What a fake or weak COA looks like in practice
Common patterns to flag:
- “Third-party tested” with no named lab
- No batch number, or the same batch number on multiple unrelated shipments
- Headline purity number (e.g., “99%”) with no chromatogram
- Chromatogram that looks identical across multiple products (suggests reused stock image)
- Mass error exactly zero (real measurements have non-zero error)
- No counterion documentation
- No analyst signature, or signature is unclear/generic
- Lab name that doesn’t return search results when verified independently
Where to go from here
For the broader framework on COA evaluation, see the complete COA guide. For PeptideDropship’s specific COA standards, every wholesale peptide page documents the per-batch analytical practice — see the BPC-157 page as an example, or browse the full wholesale catalog.
Verified partners can request representative COAs from recent batches before placing an order. Apply for partner access.
The example COA values in this walkthrough are illustrative of a representative research-grade peptide COA. Actual COA values from any supplier (including PeptideDropship) will vary by batch and may use different lab formats. The principles for evaluation apply regardless of specific format. These statements have not been evaluated by the FDA. Not intended to diagnose, treat, cure, or prevent any condition. For research purposes only — not for human consumption.
Ready to evaluate PeptideDropship?
Apply for verified partner access. Verification typically completes within 1–3 business days. After approval you get partner-specific wholesale pricing, sample COAs, compliance templates, and payment processor introductions (subject to third-party approval).
Start a Partner Application →B2B only. Research use only. Not for human consumption.