How to read a research-peptide certificate of analysis (COA)

Anatomy of a research-peptide COA

A well-formed COA for a research peptide typically carries these sections, in some order:

• Header — product name, stated sequence, lot (or batch) number, test date, and the name of the analytical laboratory.
• Identity — a mass-spectrometry readout (observed vs. expected molecular mass).
• Purity — an HPLC chromatogram with an integrated purity figure.
• Appearance — a note about the physical form (lyophilized powder, cake colour, residual moisture if measured).
• Storage recommendation — temperature and protect-from-light guidance for the specific lot.
• Signature or stamp — the lab that performed the analysis.

Lot number and test date

The lot number is the link between the paper (the COA) and the physical vial on your bench. Match the lot on the COA to the lot printed on the vial label before trusting the numbers. The test date is the date identity and purity were measured — not an expiration date and not a manufacturing date.

Identity: mass spectrometry

Mass spectrometry measures the mass-to-charge ratio of ions produced from the sample. The report quotes the observed molecular ion mass against the mass expected from the stated amino-acid sequence. A match within a few daltons (or a few parts per million on a high-resolution instrument) supports the identity claim. Common ionisation modes: electrospray ionisation (ESI) and matrix-assisted laser desorption/ionisation (MALDI).

What MS does not answer: purity. A sample can contain the right peptide and still carry impurities that MS alone will not count. That is what HPLC is for.

Purity: HPLC chromatogram

High-performance liquid chromatography pushes the dissolved sample through a packed column at high pressure, and a detector records signal over time. The output is a chromatogram whose peaks correspond to components in the sample. For a research peptide, the target-peptide peak should dominate; any smaller peaks represent related impurities (synthesis by-products, degradation products, residual reagents).

• Detection. UV absorbance at a fixed wavelength is typical (214 nm or 220 nm for peptide bonds).
• Retention time. How long after sample loading the peak emerges — a reproducible fingerprint under a fixed method.
• Peak area. Integrated signal under the curve; the input to the purity percentage.

The headline purity %

The headline is a single percentage, e.g. “99.XX%”. It is the integrated area of the target-peptide peak divided by the sum of all peak areas on the chromatogram, at the detection wavelength. A few caveats:

• The figure applies to the chromatogram shown — a method change can change the number.
• Impurities that don’t absorb at the detection wavelength won’t be counted. Inorganic salts, for example, are typically invisible on a UV chromatogram.
• A high purity figure is not a biological-activity statement.

Reading a two-peptide COA

A COA for a two-peptide vial (such as the BPC-157 + TB-500 research blend covered on this site) reports both peptides on one page:

• The chromatogram shows two expected main peaks instead of one. The method must resolve them from each other and from any impurity peak.
• The MS section shows two expected molecular masses instead of one — one for each peptide.
• Per-component purity is reported per peak, not for the vial as a whole.

Longer walkthrough: purity testing methods. For multi-peptide vials with three or four components (GLOW, KLOW), the same rules apply with more peaks and more expected masses — see the Wolverine vs GLOW vs KLOW composition page.

What a research-peptide COA does not report

• Suitability for any use. Research-use-only material is not for human or veterinary use. A COA is a chemistry document; it is not a safety data sheet and it is not clearance to use the material for anything in particular.
• How to use the material. Amount per use, route, schedule — none of that appears on a research-peptide COA. This site does not provide any of it either.
• Biological activity, efficacy, or outcomes. Not a COA output. The COA reports chemistry, not biology.
• Stability over time. The chromatogram and spectrum are a snapshot at the test date. For stability framing see the lyophilized peptide storage overview.

Quick checklist when a COA lands

1. Match the lot number on the COA to the vial label.
2. Check the test date — is this the right lot’s report?
3. Confirm the stated sequence or peptide name matches what you ordered.
4. Read the MS section: observed mass vs. expected mass. For multi-peptide vials, one mass per component.
5. Read the HPLC chromatogram: main peak(s) dominate? Impurity peaks small? Headline purity in the expected range for the vendor’s stated grade?
6. File the COA with the vial record under the lot number.

The live Wolverine Blend COA

The current Wolverine Blend lot’s COA is linked from the batch documentation page. That page also carries the latest supplier COA PDF when the supplier publishes it on the product listing.

Frequently asked questions