How to Verify Research Peptide Purity
In research, your results are only as reliable as your inputs. An impure or mislabeled peptide introduces variables you can't control. Before purchasing, here's how to verify what you're actually getting.
What a Certificate of Analysis (COA) tells you
A COA is the lab document that reports a specific batch's identity and purity. A meaningful COA shows:
- Purity % — usually by HPLC (e.g., ≥99%)
- Mass confirmation — by mass spectrometry (MS), verifying the peptide is the correct molecular weight
- Batch/lot number — so the COA traces to the vial in your hand
- Test date and method
HPLC vs. Mass Spec — what each proves
- HPLC (High-Performance Liquid Chromatography) measures how much of the sample is the target peptide vs. impurities — this is your purity number.
- Mass spectrometry confirms identity — that the molecule is the peptide it claims to be, at the right mass.
Together they answer the two questions that matter: is it the right compound, and how pure is it?
Third-party vs. in-house testing
In-house numbers can be accurate — but independent, third-party testing removes the conflict of interest. A supplier willing to publish third-party HPLC results is signaling confidence in the batch.
Red flags before you buy
- No COA available — walk away
- No batch/lot number, or a COA that doesn't match the lot
- Vague claims ("high purity") with no method or percentage
- No third-party verification
How Vital Chems handles it
Every Vital Chems batch is third-party HPLC tested at ≥99% purity, with a COA included on every order — viewable on our lab results page before you buy. No guesswork.
See the proof: Lab Results & COAs · Browse the catalog.