How to read HPLC purity on a peptide CoA
What an HPLC purity percentage means for research materials — and what it does not claim about use, safety, or biological effect.
What HPLC purity reports
High-performance liquid chromatography (HPLC) separates components in a sample under a defined method. On many peptide Certificates of Analysis, purity is reported as the percentage of the main peak relative to detected peaks under that method.
What to check on the CoA
- Method reference — HPLC (and related MS) methods should be stated or implied by the testing lab.
- Purity % — the main-peak percentage for that lot (e.g., 99.9%).
- Batch / Test ID — must match the vial label for the lot you received.
- Identity — purity alone does not replace identity confirmation (often MS / HPLC-MS).
Limits of the number
HPLC purity is analytical data for a specific lot under a specific method. It is not a medical clearance, a dosing guide, or proof that a material is suitable for human use. Different methods and labs can produce different numbers for similar-looking materials.
Related documentation
Mass content, appearance, and contamination screens (when provided) should be read together with purity — not in isolation. See also our overview of what a peptide CoA shows.
Pure Lot Lab posture
All materials are for research use only. Not for human consumption. Not intended to diagnose, treat, cure, or prevent any disease.