How to Read an Ashwagandha Extract COA, Line by Line

The header: is this COA for the lot you were offered?

Before any number, match three things. The COA number and the batch number must be printed on the document and must match the pro forma invoice and the drum label. The manufacturing and expiry dates must be consistent with the shelf life on the specification (36 months for a sealed drum is the trade norm) and with the date you expect to receive the goods. A COA with no batch number, or with a batch number that does not appear anywhere else in the paperwork, is a template, not a certificate.

The header also states the standardisation and its method — for example “Withanolides 2.5% (HPLC)”. If the method is missing here, look for it in the assay row; if it is missing there too, ask, because gravimetric and HPLC figures for the same powder can differ by a factor of two.

Identity

Identity confirms the material is Withania somnifera root and not leaf, another species or a blend. The trade minimum is a TLC profile against a reference standard; better laboratories run HPTLC with the fingerprint image attached. Neither tells you the plant part on its own — the withaferin A figure does that (see below) — so identity plus assay profile together are what confirm “root only”.

Physical parameters

Line	Typical limit	Why it matters
Appearance, colour, odour, taste	Light to dark brown fine powder; characteristic	A pale or off-white powder with a bitter-free taste is a signal of carrier dilution or a different material.
Loss on drying at 105°C	NMT 10.0% w/w	Moisture drives caking and microbial growth; hydroalcoholic extracts should sit well under the limit.
pH of a 1% solution	3 to 7	An outlier suggests unusual processing or additives.
Bulk density	NLT 0.25 g/mL	Sets capsule fill and blend behaviour; compare across lots.
Solubility in water	NLT 60 to 70% w/w	Hydroalcoholic extracts are partly soluble; a very high figure with a high assay deserves a question.
Total ash	NMT 15.0% w/w	High ash means mineral or soil load; acid-insoluble ash, if reported, catches sand.
Particle size	NLT 95% through 40 mesh	Flow and dissolution; a coarser lot behaves differently in a blend.

The assay row

This is the line the price is built on, and it needs three pieces of information: the limit (NLT 2.5%, NLT 5%), the result (a number, not “complies”), and the method. On an HPLC certificate the result is compound-specific and, on request, the laboratory can attach the chromatogram and the breakdown by withanolide glycosides and aglycones. On a gravimetric certificate the result is a weighed fraction and reads higher for the same root. Both are legitimate; what is not legitimate is a gravimetric number presented as if it were HPLC. Our guide on gravimetric versus HPLC withanolide assays explains the gap.

Two further lines are worth asking for even when they are not printed by default: withaferin A as a number (root extracts run low; a high value points to leaf material) and the extraction solvent and herb-to-extract ratio, which tell you what the powder is concentrated from.

Contaminants

Heavy metals by ICP-MS are the minimum: lead, arsenic, cadmium and mercury as numbers in ppm, against limits such as Pb NMT 1.0, As NMT 1.0, Cd NMT 0.3, Hg NMT 0.1. “Complies” is acceptable for metals only when the laboratory and the limit are both stated. For an EU shipment the COA should also carry a pesticide multi-residue screen reported against Regulation (EC) 396/2005 MRLs, an ethylene oxide result with its limit of quantification, PAH and aflatoxins where the buyer’s specification names them, and residual solvents against USP <467> for any hydroalcoholic extract. Our published shatavari COA shows what that EU panel looks like on a document; the ashwagandha export lot carries it on request.

Microbiology

Total aerobic count (typical ceiling 1,000 or 10,000 cfu/g depending on the specification), yeast and mould (100 or 1,000 cfu/g), and absence tests for E. coli, Salmonella and S. aureus. The method matters less than the sampling: microbiology on a lot sampled months ago says little about the drum in front of you, so for sensitive applications ask for a retest date.

The six checks

1. Batch number on the COA matches the drum label and the invoice.
2. The assay line carries a limit, a numeric result and a named method.
3. Withaferin A is low or reported, confirming root material.
4. Heavy metals are numbers by ICP-MS, not “complies” without a limit.
5. The laboratory is named, in-house or third party, and a third-party retest is offered.
6. Dates are internally consistent with the stated shelf life.