Does a certificate of analysis prove a product is sterile and endotoxin-free?
Updated: 2026-09-09 · Buying, quality and COA
Short answer
No — unless the certificate explicitly includes those tests. Sterility and bacterial endotoxins are measured by specific assays, separate from purity or identity. Most 'research' peptide COAs cover only identity and purity, so the absence of microbial contamination simply has not been demonstrated.
In plain English
- Endotoxin is bacterial cell-wall residue: it can be present even with no living bacteria.
- The endotoxin assay differs from the sterility assay, and both differ from purity.
- If the COA does not name them, they were not run. Do not assume them.
- A research-labelled product is not manufactured under the requirements for an approved injectable.
What we know
- Sterility and endotoxin testing are formally defined assays in pharmaceutical regulation.
- Research-labelled products are not made as approved sterile medicines.
What we don't know yet
- Without the specific assay there is no way to know a vial's endotoxin level.
- The look of the powder or vial tells you nothing about contamination.
Sources
External links to official sources or peer-reviewed studies.