Identity, Purity and Potency Explained
Identity, purity and potency are related quality concepts, but they are not synonyms. Knowing the difference makes it easier to interpret laboratory documentation without making unsupported assumptions.
Identity: what is the material?
Identity testing assesses whether a sample matches the expected substance using one or more analytical techniques. The strength of the conclusion depends on the specificity and suitability of the method and the reference material used.
Purity: what else is detected?
Purity describes the proportion or profile reported by a defined test. Results can depend on the analytical method, detection limits and how peaks or components are calculated. A single purity figure should not be read as a complete inventory of every possible impurity.
Potency: how much activity or content?
Potency can refer to the amount of a defined active component or to a measured biological activity, depending on the context and method. Those meanings are not interchangeable. A chemical assay and a functional bioassay may answer different questions.
Other dimensions of quality
Quality may also involve water content, residual solvents, degradation products, microbial controls, packaging integrity and stability. Which tests are appropriate depends on the material and lawful intended use. One certificate rarely answers every possible quality question.
How to compare reports
Compare like with like: same method, units, criteria and type of result. If reports use different methods or unexplained terms, avoid ranking them based on a single number. Ask for the method and interpretation, and retain traceable records.
Frequently asked questions
Can a high purity number prove potency?
No. Purity and potency are distinct measures and need suitable, clearly described methods.
Does identity confirmation prove the sample is uncontaminated?
No. Identity testing does not automatically screen for every impurity or contaminant.
Where to verify research claims
Use primary literature and official records to check the exact study, publication status and current regulatory position.