Most herbal extracts are exactly what the label says. But not all of them, and the ones that aren't can be hard to spot. A powder is a powder. Once a plant has been dried, milled and extracted, you can't tell root from leaf, or one species from its cheaper cousin, just by looking at it. That's why identity testing exists, and why it's worth understanding even if you never set foot in a lab.
In short: adulteration usually means a cheaper plant, a cheaper plant part, or an added chemical that pushes the test result up. The most useful protection is a combination of the right tests, a supplier who can trace the raw material, and a specification that names the plant part and the test method.
What adulteration actually looks like
It's rarely dramatic. In practice, it tends to fall into a few patterns:
- Species substitution: a related, cheaper species sold under the name of the expensive one.
- Plant part swaps: leaves or stems used where the specification says root, because they're cheaper and easier to harvest.
- Spiking: adding a pure chemical, sometimes synthetic, so the extract passes a simple assay for its marker compound.
- Dilution: a genuine extract stretched with fillers, cheaper extracts or excess carrier.
- Dyes: colours added so a weak or wrong extract looks right.
The motive is almost always the same: the genuine material is expensive or in short supply, and the buyer is only checking one number.
Which ingredients are most at risk?
The Botanical Adulterants Prevention Program, a partnership led by the American Botanical Council with the American Herbal Pharmacopoeia and the University of Mississippi, has published dozens of reviews on this. Some of the ingredients it has covered will be familiar to most supplement brands:
| Ingredient | Kinds of adulteration reported |
|---|---|
| Ashwagandha | Aerial parts (leaves, stems) used in place of, or mixed with, root |
| Grape seed extract | Cheaper sources of similar compounds, such as peanut skin or pine bark |
| Ginkgo leaf extract | Added pure flavonoids, such as rutin and quercetin, to meet flavonoid specifications |
| Turmeric and curcumin | Synthetic curcumin, and dyes in some powders |
| Bilberry extract | Anthocyanins from other, cheaper fruits, and added colours |
Being on this list doesn't mean an ingredient is usually fake. It means the risk is known, so the testing needs to be designed with that risk in mind.
The tests that actually help
HPTLC fingerprinting
High-performance thin-layer chromatography separates the compounds in a sample into a pattern of bands, a bit like a barcode, and compares it with an authenticated reference. It's quick, affordable and good at showing whether the overall chemical profile looks right, including whether a different plant part has crept in. Pharmacopoeia identity tests often use it for exactly that reason.
HPLC assay and fingerprint
HPLC measures specific compounds precisely. It tells you how much withanolide, curcuminoid or flavonoid is present, and a fuller HPLC fingerprint can reveal ratios between compounds that don't match the real plant. That's useful against spiking: if one marker is high but its natural companions are missing, something has been added.
DNA barcoding
DNA testing compares short, standard sections of a plant's genetic code with a reference library. It's excellent for raw herbs and simple powders. It's much less reliable for extracts, because extraction, heat and solvents break down DNA, so a genuine extract can fail to give a result. For extracts, chemical fingerprinting is usually the better tool, with DNA testing reserved for the raw material that went in.
Microscopy and organoleptic checks
For whole and powdered herbs, a trained analyst looking at cell structures under a microscope can spot wrong plant parts or fillers. Simple checks of colour, smell and taste against a reference still catch more problems than most people expect.
No single test proves identity on its own. The strongest approach is two different methods that agree, for example HPTLC plus an HPLC assay, on material that can be traced back to its raw herb.
What to put in your specification
You don't need to run these tests yourself. You need your supplier to run the right ones, and your specification is where you ask for them:
- Botanical name in Latin and the plant part, for example "Withania somnifera root only"
- An identity test by HPTLC against a reference standard
- The marker compound, percentage and the method (HPLC preferred over UV for most markers)
- Raw material identity checked on arrival at the factory, by microscopy, HPTLC or DNA
- No added colours, synthetic markers or undeclared carriers
- Batch traceability from extract back to raw material lots
Then read the batch COA against it. Our guide on how to read a COA shows what each line should look like.
Warning signs before you buy
- Assay results that land on the exact minimum, batch after batch
- A price well below every other quote for the same specification
- No plant part stated, or "whole plant" where the traditional part is the root
- Identity reported as "complies" with no method
- A supplier who can't say where the raw material comes from
How we approach identity at Arizone
At Arizone International LLP we state the botanical name and plant part on every specification, and our certificates of analysis report identity and assay with the method used. If your quality team needs a specific identity test, such as HPTLC against a named reference or a DNA test on the raw herb, tell us when you enquire and we'll confirm what can be provided for your batch. You can browse our herbal extracts and herb powders, and see our certificates. We supply export customers only.
Sources: ABC-AHP-NCNPR Botanical Adulterants Prevention Program; Botanical ingredient forensics (PMC review).
Identity Testing Questions
It's when an extract isn't what the label says: a cheaper species or plant part, added chemicals to boost a test result, fillers, or dyes.
Not reliably. Extraction breaks down DNA, so genuine extracts can fail to give a result. DNA testing works best on raw herbs and simple powders; chemical fingerprinting such as HPTLC suits extracts better.
HPTLC creates a chemical fingerprint of a sample and compares it with an authenticated reference, which helps confirm the right species and plant part.
Yes. If only one marker is tested, adding that compound can make a weak or wrong extract pass. Combining an assay with a fingerprint test makes this much harder.
Industry reviews have covered ingredients such as ashwagandha, grape seed, ginkgo, turmeric and bilberry, usually where the genuine material is expensive or in short supply.