Home · Peptide basics · Buying smart · lesson 4 of 13
Buying smart
Endotoxins and sterility: what lab reports can miss
The contamination tests most peptide COAs don't include, and why they matter.
Purity and quantity tests don't tell you whether a product is free of contamination. Two other tests do:
- Endotoxins are fragments of bacterial cell walls. They survive filtration and heat and can cause fever and inflammation. Labs measure them with the LAL test, reported in endotoxin units (EU).
- Sterility testing checks for live bacteria or fungi.
Approved injectable drugs must pass both. Most research-peptide COAs include neither, so a clean HPLC result doesn't mean a product is sterile. When a vendor does publish endotoxin results, that's a point in its favour.
Key points
- Purity tests don't check for contamination.
- Endotoxin (LAL) and sterility tests are separate.
- Most research-peptide COAs don't include them.
Quick check
A COA shows 99.8% purity by HPLC and nothing else. Does it show the product is sterile?
HPLC measures purity of the peptide, not microbial contamination or endotoxins.
Sources
General education, not medical advice. Nothing here recommends using any compound or amount.