Two gokshura powders can both be “standardised” and still describe completely different materials — because total saponins by UV and protodioscin by HPLC measure different things. A 90% UV number and a 20% HPLC number are not a contradiction; they are two lenses on the same steroidal-saponin chemistry. Confusing them is the most common and most expensive mistake in tribulus procurement. Here is how to read each and specify the right one.
Total Saponins by UV-Vis
The UV-Vis spectrophotometric method quantifies the whole steroidal-saponin fraction after a colour-forming reaction. It is fast, inexpensive and the long-standing trade method for tribulus, which is why grades are sold as 40%, 60% and 90% saponins. Its strengths and limits:
- Broad. It captures the total saponin pool, not any single molecule — a good measure of overall concentration.
- Method-sensitive. The number depends on the reference standard and reaction conditions, so two labs can report different “totals” on the same powder. Always note the method basis.
- Not compound-specific. A high UV total says nothing about how much protodioscin is present.
Protodioscin by HPLC
High-performance liquid chromatography separates and quantifies protodioscin specifically. It reads far lower than the total-saponin figure — a material at 60% total saponins by UV might carry only a single-digit-to-low-double-digit protodioscin percentage by HPLC — but it is reproducible and molecule-specific:
- Defined. It measures the named actives that research actually studied.
- Comparable. An HPLC protodioscin figure means the same thing from lab to lab, unlike a UV total.
- Label-grade. It is what monograph-style and clinical-dose labels increasingly require.
The core point: a high UV saponin number is a concentration signal; an HPLC protodioscin number is an identity-and-potency signal. Neither is “better” in the abstract — the right one depends on what your label claims.
Which One Should Be on Your Spec?
| If your label… | Specify | Why |
|---|---|---|
| Leads on a saponin % (e.g. “standardised to 60% saponins”) | Total saponins by UV | Matches the headline number to the trade method |
| References protodioscin or clinical-style dosing | Protodioscin by HPLC | Matches the label to the studied molecule |
| Needs both marketing punch and a defined active | Both, same batch | UV for the front-of-pack number, HPLC for QA and substantiation |
How SV Botanica Reports It
SV Botanica standardises gokshura by total saponins (UV) at 40/60/90% and offers a separate protodioscin-standardised (HPLC) grade. Critically, the same fruit material can be reported by both methods on the batch documentation — so you can carry a UV number on the label and an HPLC protodioscin figure in your QA file without re-sourcing. The 40% reference batch assayed 42.6% total saponins by UV.
Two Rules for the Purchase Order
- Always state the method. “60% saponins” is incomplete; “60% total saponins by UV-Vis” is a specification.
- Never compare across methods. A UV total from one supplier and an HPLC figure from another are not comparable quotes — normalise the method before you compare price.
For grade selection and CoA essentials, see the buyer’s guide; for the chemistry behind the markers, tribulus saponins & protodioscin.
Need the Method Matched to Your Label?
40/60/90% total saponins (UV) · protodioscin standardised (HPLC) · same batch reported both ways on request