Does a peptide COA prove sterility?
Short answer · as of 2026-10-05
Only if the report lists a sterility test, with its method and result. An endotoxin result is a different test and does not show sterility. FDA's aseptic-processing guidance says sterilizing filters and moist heat have not been shown to remove endotoxin, so sterility and endotoxin control are separate questions. A report that lists neither says nothing about either.
By Peptide Industry Gossip · Published · General explanation, not legal or medical advice. Disclaimer.
Two different questions
- Sterility: whether viable microorganisms are present. It needs a sterility test on the sample.
- Endotoxin: whether bacterial endotoxin is present. FDA's Q&A describes gel-clot, photometric and kinetic methods.
What FDA says
FDA's aseptic-processing guidance says sterilizing filters and moist heat have not been shown to remove endotoxin, so depyrogenation needs its own validation, and 21 CFR 211.167(a) requires testing for products purporting to be sterile or pyrogen-free. Our inference: a sterility result does not cover endotoxin, and an endotoxin result does not show sterility.
What to check on a report
- Is a sterility test named, with a method, a result and the sample tested?
- Is an endotoxin test named, with a method and a limit?
- Does the sample match the product and lot? A bulk-lot result does not describe the contents of a filled vial.
What this does not tell you
A sterile or low-endotoxin result does not make a product suitable for injection, and we do not give a level that counts as acceptable. See our guide to the tests a COA may include.
Sources
- FDA, Sterile Drug Products Produced by Aseptic Processing (Sept. 2004)
- FDA, Pyrogen and Endotoxins Testing: Questions and Answers (Edition 2, March 2026)