Method
How potency is measured
Reversed-phase HPLC with UV detection against a certified reference standard. Identity and purity are reported alongside, but potency is the determinative number.
Why potency, not purity, is the number that matters
Purity describes what fraction of the material present is the target compound. It clears specification in the substantial majority of samples. Potency describes how much of that compound is actually there — and a vial can be 99% pure and still hold 28% less peptide than the label claims, because the remaining mass is counterion, residual water and excipient. Purity is about composition. Potency is about the dose.
The assay
- Technique
- Reversed-phase HPLC, UV detection
- Instrument
- model
- Reference standard
- source and grade
- Limit of detection
- LOD
- Limit of quantitation
- LOQ
- Recovery
- %
- Intra-assay CV
- %
Every figure above is stated on the certificate. The whole defensibility of a potency number rests on the reference standard, so it is named, not implied.
What the method does not tell you
Potency and purity describe the peptide. They say nothing about sterility, endotoxin load, or heavy metals. Whether those are offered is panel scope.