RESEARCH USE ONLY. Reference data for laboratory research. Not medical advice; not for human consumption.
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How to read a COA

A certificate of analysis (COA) is the lab report for one batch. First make sure it belongs to your vial, then check what it says.

Part 1

Match the vial to the report

Three places on the vial each point to lines on the certificate. Tap through them; the matching lines light up.

Use the arrow keys to move between the three vial parts. Matching certificate lines are marked as highlighted.

Front

Example Peptide

10 mg

(highlighted — check this)

Side

Lot PJ-2410-07

Scan for COA

Certificate of analysis

  • Example Peptide · 10 mg (highlighted — check this)
  • LotPJ-2410-07
  • Purity99.1%
  • MassMatch
  • Tested2026-09-12
  • LabIndependent

Step 1 of 3 · Front label

Product + strength

The name and mg amount on the front should match the product named at the top of the certificate. A different compound or strength means it's the wrong report.

Step 1 of 3: Front label, Product + strength. Highlighted on the certificate: product name and strength.

Illustrative example — label layouts vary by supplier.

Part 2

The 5 parts that matter

  1. 1

    Purity (HPLC)

    Percent of the sample that is the target peptide. Research-grade listings commonly report ≥98%.

  2. 2

    Identity (mass spec)

    Measured molecular mass should match the compound's expected mass.

  3. 3

    Lot / batch number

    Must match the number printed on your vial.

  4. 4

    Test date

    Recent testing of the specific batch, not a years-old sample.

  5. 5

    Testing lab

    Independent third-party labs are generally preferred over in-house results.

Part 3

When to walk away

Red flags

  • No lot number, or it doesn't match the vial
  • Purity under 98% or not stated
  • No test date, or a very old one
  • Generic COA reused across products
Glossary: HPLC, mass spec →Full research guide →Find supplier COAs on compound pages →

Research use only. A certificate describes what a lab measured in one batch; it is not an endorsement of any use. Examples on this page are illustrative.