What it means for a research store
Endotoxins are lipopolysaccharides from the outer membrane of Gram-negative bacteria. They are heat-stable and can persist after the bacteria are gone, so a material can be sterile and still contain endotoxin. Laboratories measure them in endotoxin units (EU), commonly per milligram or per millilitre.
The traditional assay uses Limulus amebocyte lysate, which reacts with endotoxin through gel-clot, turbidimetric or chromogenic readouts. Recombinant factor C assays reproduce the key reaction without the animal-derived reagent. Results are reported against a limit, and the COA should state the method, the limit and the measured value.
For a research-supply store, endotoxin data is one more lot-specific result. Publish it as reported, attached to the matching lot, and do not generalise it into safety claims. If some lots have endotoxin results and others do not, the product page should make that clear rather than implying every lot was tested. Endotoxin testing is separate from sterility testing and from purity; one does not substitute for another.
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Updated September 25, 2026. General information for merchants, not legal, tax or financial advice. This glossary does not describe the use of any compound in people.
