The US Food and Drug Administration (FDA) has published guidance for dietary supplement manufacturers on what it considers to be sufficient scientific substantiation for the health claims made on their products.

The guidance, which takes the form of recommendations rather than rulemaking, refers to all nutritional deficiency, structure/function or general well-being claims.

Published last month and open to comment from industry, it describes the amount, type and quality of evidence that FDA considers necessary to substantiate claims under section 403(r)(6) of the Federal Food, Drug, and Cosmetic Act.

Neither this act nor the Dietary Supplement Health and Education Act (DSHEA), which amended it in 1994, define ‘substantiation’, prompting the current guidance from FDA.

The agency drew on its own enforcement experience as well as that of the Federal Trade Commission (FTC), which is in charge of regulating product advertising. FDA also drew on recommendations from the Commission on Dietary Supplement Labels, an advisory body established under DSHEA.

The new guidance, which is modeled on an FTC guidance document published in 2001, recommends that supplement manufacturers review the support for each label claim to ensure that it relates to the specific product and claim, is scientifically sound, and is adequate in the context of the surrounding body of evidence.

Substantiation standards

According to FTC, competent and reliable scientific evidence needed to back a substantiation standard constitutes "tests, analyses, research, studies, or other evidence based on the expertise of professionals in the relevant area, that has been conducted and evaluated in an objective manner by persons qualified to do so, using procedures generally accepted in the profession to yield accurate and reliable results.”

FDA, which it is applying a standard consistent with FTC’s interpretation of ‘competent and reliable scientific evidence’, said the major factors that establish whether information meets this standard are:

• Does each study or piece of evidence bear a relationship to the specific claim(s)?


• What are the individual study's or evidence's strengths and weaknesses? Consider the type of study, the design of the study, analysis of the results, and peer review.


• If multiple studies exist, do the studies that have the most reliable methodologies suggest a particular outcome?


• If multiple studies exist, what do most studies suggest or find? Does the totality of the evidence agree with the claim(s)?

FDA’s guidance document provides a discussion of each of these points, together with examples of claims that might be made for dietary supplements. To access the guidance, click here.