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Testing

What Does “Third-Party Tested” Mean?

Why the phrase alone tells you very little, and what to look for instead.

Updated September 28, 20261 min readBy the SuppScout Editorial Team
The short answer

“Third-party tested” means the manufacturer says an outside lab tested something. Without the lab’s name, what was tested and the result, you can’t verify it. A named certification program with a public listing — like USP Verified or NSF Certified for Sport — is much more informative.

Key takeaways
  • There is no legal definition of “third-party tested” on supplement labels.
  • Ask: who tested it, what did they test for, and where can I see the result?
  • Certification programs publish listings you can check yourself.

The phrase isn’t standardized

Dietary supplements in the U.S. don’t need FDA approval before sale, and there’s no regulatory definition of “third-party tested”. A company might send one batch for a single test, or test every batch for identity, potency and contaminants. The phrase covers both.

Three questions to ask

  • Who did the testing? (A named lab or certification body)
  • What was tested? (Identity, amount per serving, heavy metals, microbes, banned substances)
  • Where is the result? (A certificate of analysis, or a listing on the certifier’s site)

Named certification programs

Programs such as USP Verified, NSF Certified and NSF Certified for Sport, and Informed Sport publish lists of certified products. Each program tests different things. None of them evaluates whether a supplement is effective or appropriate for you.

How SuppScout labels testing

On SuppScout, a certification appears as verified only if we’ve confirmed the product in the certifier’s public listing, with the date we checked. A generic testing statement appears as a manufacturer claim. If nothing is available, we show Not verified rather than guessing.

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Sources & references

  1. Dietary Supplements. U.S. Food and Drug Administration. fda.govRegulatory
  2. Dietary Supplement Verification Program. U.S. Pharmacopeia (USP). usp.orgOrganization
  3. NSF Certified for Sport. NSF. nsfsport.comOrganization
  4. NSF Certified Dietary Supplements listings. NSF. info.nsf.orgOrganization
  5. Informed Sport. LGC ASSURE. sport.wetestyoutrust.comOrganization

SuppScout links to primary and authoritative sources wherever possible. See our editorial policy for how sources are selected and how corrections are handled.