A field guide · research use only
How to check a peptide certificate of analysis
A certificate of analysis is a claim about a batch, printed by whoever wanted you to believe it. Some are genuine third-party lab reports. Most are not. Here is how to tell the difference in about five minutes, using only the document in front of you.
What a real certificate proves — and what to distrust
A Certificate of Analysis says what's in a batch and how pure it is. Two tests do the heavy lifting: HPLC measures purity, mass spec confirms identity. Here's what to check by eye — and what Peptora checks for you on every upload.
HPLC purity + chromatogram
One tall, clean peak at ≥98%. A single high percentage isn't enough — secondary peaks or a noisy, drifting baseline mean the real purity is lower than the headline number.
Scores the claimed purity and flags implausible values.
Mass spec identity
Observed mass within ~5 ppm of the theoretical mass confirms it's the right molecule. A loose ±0.1% tolerance is a warning — on a 3,000 Da peptide it can hide a truncated or wrong sequence.
Recomputes the mass from the sequence and gates on a mismatch.
Batch / lot number
Must match the lot printed on the vial you received. If they don't match, the certificate simply isn't for your material.
Every record is tied to a batch; a second buyer's upload corroborates it.
Testing lab + date
A named, accreditable lab (look for A2LA or ILAC) and a recent test date. “In-house,” unnamed, or undated results can't be independently verified.
Records the lab and date and surfaces them on the public permalink.
Contamination panel
Endotoxins as an EU/mg number (not just “pass”), plus heavy metals and residual solvents. A purity COA alone says nothing about what else is in the vial.
Shows tested / not-measured coverage across every COA on the batch.
Authenticity + reuse
The same certificate shouldn't appear across different products or batches, and the file shouldn't show signs of editing.
Fingerprints the file and flags tampering and cross-party reuse.
- Every product in the range shows exactly >99% — real synthesis yields vary by sequence and length, so uniform numbers are statistically implausible.
- A flawless, noise-free chromatogram — genuine HPLC data always has minor baseline noise.
- Endotoxins reported as “pass” with no EU/mg value.
- A missing test date, or a certificate that's years old.
- A COA only emailed on request and never published openly.
- A batch number on the paper that doesn't match the vial.
For research use only — nothing here is medical, dosing, or purchasing advice.
Every check above is a check on a document. Even one that passes them all proves only that a laboratory tested a sample somebody sent it. It cannot establish that the vial in your hand came from that batch.
Check a certificate