Specifications are full of percentages, and they do not all mean the same thing. Reading them correctly is the difference between comparing two offers fairly and comparing apples to oranges.
Assay #
Assay is the measured content of the ingredient or its marker compound, expressed as a percentage. “Apigenin ≥98%” means at least 98% of the material is apigenin, as measured by the stated method. Two things travel with every assay figure and should never be dropped:
- The method — HPLC, UV, titration, and gravimetric methods can return different numbers for the same material. A 98% by UV is not automatically equal to 98% by HPLC.
- The basis — “on the dried basis” or “as is” changes the result once moisture is accounted for.
Purity vs. assay #
Assay tells you how much of the target you have; purity is about what else is present. A high assay can still sit alongside limits you care about — heavy metals, residual solvents, microbiology, or pesticide residues. Always read the assay line together with the contaminant limits on the same document.
Standardised extracts and ratio extracts #
Botanical extracts are described two common ways:
- Standardised — adjusted to contain a defined level of a marker compound, e.g. “Ginkgo biloba extract, 24% flavone glycosides.” This is the more precise, comparable option.
- Ratio (e.g. 10:1) — ten parts raw material concentrated to one part extract. A ratio describes the concentration process, not a guaranteed active level, so two 10:1 extracts can differ in marker content.
What to confirm before you commit #
Ask the contracting supplier for the assay method, the marker compound and its level, the basis of measurement, and a representative certificate of analysis. Specification information on SpecNexa is supplier-submitted and may change between batches; the final agreed specification should be confirmed directly with the supplier for your intended use.
