Raw ashwagandha root powder usually contains withanolides at a low level, often well under one percent, while extracts are concentrated and standardised to higher stated levels. There is no single figure every root powder must meet.
The number on a certificate also depends heavily on the test method. A minimum without a method is not a useful spec.
Root powder and extract are different products
Root powder is dried root, milled. Its withanolide level is whatever the roots contain. An extract is made by soaking root, or sometimes root and leaf, in a solvent and concentrating the result. Extracts are commonly sold standardised to a stated percentage, for example figures such as 2.5 or 5 percent.
If a supplier offers root powder with an extract-level figure, ask questions. Either the method gives inflated numbers, or the product is not plain root powder.
Why the method matters
Write the method, the compounds counted and the basis into your spec. Then compare suppliers only on results from the same method.
- HPLC measures specific withanolide compounds against reference standards. It is the method most buyers ask for.
- Older gravimetric or UV methods measure broader groups of compounds and can give much higher figures.
- Labs differ in which withanolides they add together for a total.
- Results can be reported on an as-is or dry basis.
What affects the level
- Plant variety and growing conditions.
- Root age and thickness at harvest.
- Drying and storage conditions.
- Whether stems or leaf have been mixed in.
- Fibrous root crowns and stem bases, which dilute the powder.
How to set your minimum
Test several samples from different lots by HPLC at the same lab. Use those results to set a realistic minimum that suits your formulation and label. Keep an approved sample and repeat the test on pre-shipment samples. Our guide on who should draw the sample explains why sampling matters as much as the test.
Do not chase a high figure at any cost. A root powder with an unusually high result may contain leaf. See checking ashwagandha is root only.
Safety tests matter as much
A good withanolide result does not make a lot safe. Ashwagandha is a root crop, so it can carry soil, which brings heavy metals and high microbial counts. Ask for lead, arsenic, cadmium and mercury results, pesticide residues and microbiology on the same lot.
Many supplement buyers also require identity testing and, for some markets, organic certification. Build all of these into one spec so a supplier cannot pass one test and ignore the rest. See heavy metals in herbs for the safety side.
Where we come in
We arrange HPLC testing of ashwagandha samples at NABL-accredited labs using the method you name, and draw pre-shipment samples ourselves. Share your target in a free sourcing review.