Buyers often ask for “the best grade”. There is no such thing. A 2.5% and a 10% extract from the same root are the same material at different concentrations, and the right one depends on the milligrams your format can carry, the daily withanolide dose you are targeting, and what you pay per active milligram.
Start from the daily dose, not the percentage
Published human trials on standardised root extract have used roughly 240 to 600 mg of extract per day, with withanolide content stated by the method of the study’s ingredient. Work backwards from the extract dose you want on the label, and the milligrams a format can hold per serving, and the grade falls out.
| Target per day | Grade | Extract per day | Fits |
|---|---|---|---|
| ~15 mg withanolides (equivalent) | 2.5% | 600 mg | Two 300 mg capsules; a tablet |
| ~15 mg | 5% | 300 mg | One capsule; a gummy pair |
| ~15 mg | 10% | 150 mg | A single gummy; a stick pack; a beverage shot |
The equivalence holds only within one assay method. A 5% gravimetric extract and a 5% HPLC extract do not carry the same withanolide load, so compare grades on the same basis before comparing prices.
Cost per active milligram
Higher grades cost more per kilogram and less per milligram of withanolides, until concentration starts to cost yield. In practice the 5% grade is the price-efficient centre of the market for capsules and tablets; the 10% grade earns its premium in formats with tight volume budgets; the 2.5% grade wins on multi-herb blends and cost-led private label where the extract dose is already large. Ask for a quote on two grades at the same withanolide delivery per serving and the arithmetic settles it.
Format fit
- Capsules and tablets carry 300 to 600 mg comfortably; 2.5% and 5% both work, 5% gives a single-capsule serving.
- Gummies tolerate 100 to 250 mg of extract per piece before bitterness and texture suffer; 5% or 10% keeps the piece count sensible.
- Beverages and shots need water dispersibility and a low taste load; a water-soluble grade, or a 10% grade at low inclusion, is the usual route. See the formulation guide.
- Ayurvedic and traditional formats often specify the root powder or a low-ratio extract rather than a high standardisation.
Where the method changes the answer
If your specification is written by HPLC and your supplier’s stock grade is gravimetric, the “5%” on the drum may test at half that by your method. Either accept the gravimetric basis and adjust the serving, or specify an HPLC grade from the outset. SV Botanica’s 2.5% export grade is assayed by HPLC with its COA published; the 5% standard grade is gravimetric with an HPLC profile per lot on request; 10% by HPLC is quoted to order.
A simple decision rule
- Fix the extract dose per day you want on the label.
- Fix the milligrams your format can carry per serving.
- Divide; the grade that lands the dose in one or two servings is the one to quote.
- Quote two adjacent grades on the same assay basis and compare cost per active.
Quote two grades on the same basis
Tell us the daily extract dose and the format; we quote 2.5%, 5% and 10% on a like-for-like withanolide basis.