Testing & quality

Net peptide content

Also known as: peptide content · net content

The proportion of the vial’s total mass that is actually peptide, as opposed to water, salts, counter-ions, and bulking agents.

In plain terms

This is the number people most often confuse with purity, and the confusion is expensive. Purity compares peptide to peptide-like impurities. Net content compares peptide to everything.

A vial can be 99% pure by HPLC and 70–85% peptide by mass, because the HPLC detector never registers the trifluoroacetate counter-ions, residual water, or mannitol making up the rest. If a vial labelled 10 mg is 75% net content, you have 7.5 mg of peptide.

Why it matters

Ask for both numbers. Purity alone does not tell you how much peptide you paid for, or how much you are injecting.

Guides that use this term

How to read a peptide certificate of analysis

What a real certificate of analysis contains, why 99% purity does not mean 99% peptide, and the tells that separate a laboratory measurement from a marketing graphic.

Educational reference only. Pepperz does not provide medical advice, diagnosis, treatment, prescribing guidance, or dosing recommendations.