A peptide Certificate of Analysis (COA) is a lab report verifying what a sample contains, at what purity, with what impurities. This guide walks through reading and verifying a peptide COA in under 60 seconds — applicable to any vendor’s COA, with specific examples from Janoshik Analytical reports.
What a peptide COA contains
A legitimate peptide COA has these elements. If any are missing, the COA is incomplete.
- Laboratory identification: name, address, accreditation status of the lab issuing the report. For example, Janoshik Analytical, Czech Republic.
- Sample identification: client name (vendor), compound name, lot number, sample ID.
- Test date and analyst: date the analysis was performed and initials of the analyst who performed it.
- Methodology: which analytical technique was used. For peptides, this is typically HPLC-MS (high-performance liquid chromatography with mass spectrometry).
- Purity result: percentage purity of the active peptide. Industry standard for research-grade is ≥95%; high-quality vendors target ≥98%.
- Mass spectrometry confirmation: the measured molecular weight should match the theoretical molecular weight of the peptide.
- Chromatogram: the visual peak diagram showing the main peptide peak and any impurity peaks. The shape, separation, and relative size of peaks matter.
- Impurities: any secondary peaks above background noise, with their masses identified if possible.
- Lab signature: digital or handwritten signature of the responsible analyst.
The 60-second verification process
- Confirm the lot number matches your product: the lot number on your product label or order documentation must exactly match the lot number on the COA. If they don’t match, this COA is for a different batch.
- Confirm the lab is independent: the COA should be issued by a third-party lab, not the vendor’s in-house operation. For Bastion, this is always Janoshik Analytical (independent of Bastion’s supply chain).
- Read the purity figure: ≥95% is the minimum acceptable for research-grade peptides. ≥98% is high quality. Below 95% should not be sold as research-grade.
- Confirm molecular weight: the measured MW should match the expected MW of the peptide within ~0.1 Daltons. For semaglutide, expected MW is 4113.6 g/mol; for retatrutide, ~4731 g/mol; for tirzepatide, ~4813 g/mol. Match against the value on the COA.
- Inspect the chromatogram: the main peak should be dominant, narrow, and well-separated from any impurity peaks. A single tall peak indicates high purity; multiple competing peaks indicate degradation or contamination.
- Cross-verify with the lab directly (optional, advanced): Janoshik publishes COAs at their own domain (janoshik.com). If a vendor links their COAs from the vendor’s own server only, this is a yellow flag — the document could in principle be edited. Janoshik-hosted PDFs are the cross-verification.
Red flags in peptide COAs
- No lot number, or generic lot number: “Sample 1” or “Test Batch” is suspicious. Real lots have unique identifiers.
- Old test date: a COA dated more than 12 months before your purchase suggests the vendor is reusing one test across many shipments. Look for current-month or current-quarter testing.
- In-house testing: a COA from the same company selling you the product is structurally biased.
- Missing chromatogram: a “COA” that’s just a purity number with no chromatogram, methodology section, or impurity analysis is incomplete.
- Round-number purity claims: “100% pure” is implausible — real chromatograms always show trace impurities. “99.9%” without analyst signature is suspicious.
- Inconsistent molecular weight: claimed MW that doesn’t match the peptide’s actual MW.
- PDF metadata mismatch: open the PDF properties; the “Created by” field should match the lab name, not the vendor name.
Verifying Bastion COAs specifically
Bastion Peptides uses Match-Batch verification — every production lot has an independent Janoshik Analytical COA published at /lab-results/ before shipment. To verify your batch:
- Open /lab-results/.
- Find your lot number (format YYYY-MM-DD on the product label).
- Click the linked Janoshik PDF. The link should resolve to janoshik.com, not bastionpeptides.com — confirming independence.
- Apply the 60-second verification process above.
Common questions
What if my lot number isn’t in the public archive?
Reply to your order confirmation email. Bastion will provide the Janoshik PDF directly within 24 hours. Every lot has a COA on file before shipment; absence from the archive is operational lag, not a verification gap.
How can I tell a fake or edited COA?
Cross-verify with the issuing lab. For Janoshik COAs, the PDF should load from janoshik.com servers. PDF metadata (right-click → Properties) should show “Janoshik Analytical” as creator. Vendor-hosted PDFs without a Janoshik-side cross-link cannot be cross-verified.
Is 95% purity enough?
For research use, 95% is the conventional minimum. Most contamination at 95% is residual synthesis byproducts (truncated peptides, deletion sequences), not toxic impurities. ≥98% is preferable for higher-precision research. Pharmaceutical-grade is ≥99% with full impurity characterization.
Why don’t all peptide vendors do per-batch COAs?
Cost. Each Janoshik analysis costs ~$50-200 depending on compound and turnaround. For a vendor moving 200 lots/year, this is $10K-40K in lab fees vs. zero if reusing one historical COA. The transparency tradeoff is the vendor’s choice; Match-Batch transparency is Bastion’s.
Can I send Bastion my batch for independent retesting?
Yes. Bastion will pay for one Janoshik re-analysis per researcher per year. Reply to your order confirmation. The result is published at /lab-results/ regardless of outcome.
Research use only. Not for human consumption. Not intended to diagnose, treat, cure, or prevent any disease.