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Glossary

What is identity testing of raw materials?

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

An identity test confirms that a raw material is the ingredient it is supposed to be, such as the right plant species and plant part. Under FDA's manufacturing rule (21 CFR 111.75), supplement makers must run at least one appropriate test or examination on each dietary ingredient before using it, unless FDA grants an exemption.1,2

Key facts

  • Identity is one of the specifications every finished supplement batch must have, alongside purity, strength, composition and limits on contamination.3
  • A component that fails its identity specification must be rejected and cannot be used. There is no option to rework it.4
  • Allowed approaches include sensory checks, examination by eye or under a microscope, chemical analysis, or another scientifically valid method.1
  • A supplier's certificate of analysis can confirm many specifications, but not the identity of a dietary ingredient.1,2
  • Since 2007 a maker can petition FDA to identity test fewer than all incoming lots, if it shows there is no material loss of assurance.5

Why identity comes first

Plant ingredients are hard to pin down. FDA noted that botanicals vary with the part of the plant used, where it was grown and the growing conditions each year, and that closely related species can be difficult to tell apart.2

A wrong species can carry different active compounds. FDA said the biological activity of an incorrectly identified species can lead to adverse consequences, which is one reason identity is checked before a component is used.2

Some substitution is deliberate. A 2023 review of botanical adulteration describes ingredients swapped for, diluted with or spiked with cheaper materials, sometimes in ways designed to look right on common tests.6

How labs confirm identity

  • Sensory and visual checks of whole or cut material, such as shape, color, texture and smell.1
  • Microscopy, which looks at the cell and tissue features of plant material.1,7
  • Chemical fingerprinting, such as high performance thin layer chromatography (HPTLC), which compares the pattern of compounds in a sample with authenticated material.8
  • DNA methods, which can identify species in raw plant material but have given mixed results on processed ingredients.7

No single method fits every ingredient. A review of DNA barcoding advised against using general DNA tests as the only check on processed plant material, and suggested combining DNA, chemical, microscopic and visual methods.7

What an identity test does not show

Identity answers one question: is this the right ingredient? It does not measure how much of the ingredient is present, which is the job of a strength or potency test, and it does not screen for contaminants such as heavy metals or microbes. FDA's rule sets each of these as a separate specification.3

Questions people ask

Is identity testing required for supplements in the U.S.?

Yes. Before using a dietary ingredient, a manufacturer must confirm its identity with at least one appropriate test or examination, unless FDA has granted an exemption by petition. Other components can be confirmed by a test or by a qualified supplier's certificate.1

What is botanical identity testing?

It is identity testing for plant ingredients. Reviewers recommend combining a look at the plant material, microscopy, chemical analysis and, where it works, DNA methods, because no single method suits every botanical.7

Can identity testing catch adulteration?

Often, but not always. Some adulterants are chosen to mimic the look and chemistry of the real ingredient, which is why reviews call for test methods picked to detect the specific kinds of fraud.6

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Sources

  1. 21 CFR 111.75. What must you do to determine whether specifications are met? Opened 2026-10-07.
  2. Food and Drug Administration. Current Good Manufacturing Practice in Manufacturing, Packaging, Labeling, or Holding Operations for Dietary Supplements; Final Rule. Federal Register 72 FR 34752, June 25, 2007. Opened 2026-10-07.
  3. 21 CFR 111.70. What specifications must you establish? Opened 2026-10-07.
  4. 21 CFR 111.77. What must you do if established specifications are not met? Opened 2026-10-07.
  5. Food and Drug Administration. Petition to Request an Exemption From 100 Percent Identity Testing of Dietary Ingredients; Interim Final Rule. Federal Register 72 FR 34959, June 25, 2007. Opened 2026-10-07.
  6. Gafner S, Blumenthal M, Foster S, et al. Botanical ingredient forensics: detection of attempts to deceive commonly used analytical methods for authenticating herbal dietary and food ingredients and supplements. J Nat Prod. 2023;86(2):460-472. Opened 2026-10-07.
  7. Parveen I, Gafner S, Techen N, Murch SJ, Khan IA. DNA barcoding for the identification of botanicals in herbal medicine and dietary supplements: strengths and limitations. Planta Med. 2016;82(14):1225-1235. Opened 2026-10-07.
  8. Avula B, Sagi S, Gafner S, et al. Identification of Ginkgo biloba supplements adulteration using high performance thin layer chromatography and ultra high performance liquid chromatography-diode array detector-quadrupole time of flight-mass spectrometry. Anal Bioanal Chem. 2015;407(25):7733-7746. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.