Suppose someone wants a probiotic that contains Oxalobacter formigenes. They see a paper (Ellis, 2016) that says two supplements sold with this label contain no culturable O. formigenes and no amplifiable oxc DNA. Can you suggest means by which they could identify an verifiable source of this supplement, or any other product sold as a nutritional supplement in the U.S.?

(This question does not address whether nutritional supplements are effective if taken as intended)

  • I think the answer is there aren't any, but I look forward to being proved wrong.
    – Carey Gregory
    Aug 11, 2021 at 4:01

1 Answer 1


USP is a third-party verification certification: https://www.usp.org/verification-services/verified-mark

It's private rather than governmental. On the consumer side, it is intended to achieve the following:

Seeing the USP Verified Mark on a dietary supplement label indicates that the product:

  • Contains the ingredients listed on the label, in the declared potency and amounts. Tests have shown that contents of some supplements don't match the label and some contain significantly less or more than the claimed amount of key ingredients. USP Dietary Supplement Verification helps assure customers that they are getting the value they expect from a product they are purchasing.
  • Does not contain harmful levels of specified contaminants. Some supplements have been shown to contain harmful levels of certain
    heavy metals (e.g., lead and mercury), microbes, pesticides, or other contaminants. At specific levels these contaminants can pose serious
    risks to one's health.
  • Will break down and release into the body within a specified amount of time. If a supplement does not break down properly to allow its ingredients to be available for absorption in the body, the
    consumer will not get the full benefit of its contents. USP Dietary
    Supplement Verification tests products against performance standards.
  • Has been made according to FDA current Good Manufacturing Practices using sanitary and well-controlled procedures. Assurance of safe, sanitary, well-controlled, and well-documented manufacturing and monitoring processes indicates that a supplement manufacturer is
    quality-conscious, and that the supplement will be manufactured with
    consistent quality from batch to batch.

In part, getting the certification on a per-product basis involves:

To obtain the USP Verification Mark, manufacturers must undergo:

  • Manufacturing facility audit for compliance with USP General Chapter <2750>: Manufacturing Practices for Dietary Supplements and FDA current Good Manufacturing Practices (21 CFR Part 111)
  • Review of manufacturing and quality control product documentation;
  • Laboratory testing of samples of dietary supplements for conformance to standards of quality found in the USP–NF, or to appropriate pharmacopeial or manufacturer specifications and
  • Off-the-shelf testing of USP Verified dietary supplements to confirm that the product continues to meet science-based quality standards.

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