Third-Party Testing

Third-party testing is analysis of a sample by a laboratory that is independent of both the producer and the vendor and that issues its own report. What separates it from an in-house certificate of analysis is motivation, not method: the HPLC and mass spectrometry techniques are the same, but whoever runs them has no financial stake in the result.

What a report can and cannot confirm

A worthwhile independent report establishes identity through exact mass compared with the calculated molecular weight, chromatographic purity as an area-percent value with the chromatogram included, and — if ordered — net peptide content, water and counter-ion content, sterility or endotoxin.

Its boundaries are just as clear. A report applies to a single sample from a single lot on a single date and tells you nothing about the following batch. Area-percent purity by UV at 214 nm detects species containing peptide bonds and may completely overlook contaminants that do not absorb; residual solvents, heavy metals and microbial content are separate tests that have to be requested specifically.

Check the report as well: a named laboratory, an analysis date, a lot number that matches the vial, and a chromatogram attached instead of just a summary table. A PDF lacking these features is an assertion, not proof.

Related terms and material

purity · gray-market vendor · FDA-approved vs research-grade. Further reading: third-party testing explained, how to read a peptide COA and verifying a lot yourself.