“Master Files” are not just for PowerPoints. On April 4, 2024, the Food and Drug Administration (FDA) issued its “New Dietary Ingredient Notification Master Files for Dietary Supplements: Guidance for Industry” (“Draft Guidance”). These latest recommendations build upon the agency’s Final Guidance issued in March—the subject of our prior blog post—regarding procedures and timeframes for industry stakeholders to submit NDINs. The new recommendations also replace and expand upon those portions of a 2016 Revised Draft Guidance, called “Dietary Supplements: New Dietary Ingredient Notifications and Related Issues,” related to Master Files. As set forth below, this latest guidance from FDA offers no surprising revelations. What is remarkable is the extraordinary length of time, even by FDA standards, that it is taking to provide the dietary supplement industry with firm guidance matters related to “New Dietary Ingredients” (NDIs).

An NDI is defined in the federal Food, Drug, and Cosmetic Act (“FD&C Act”) as “a dietary ingredient that was not marketed in the United States before October 15, 1994 and does not include any dietary ingredient which was marketed in the United States before October 15, 1994.” A manufacturer or distributor of an NDI, or dietary supplement containing an NDI, must submit a premarket notification to FDA at least 75 days before introducing the product into interstate commerce unless the NDI and other dietary ingredients in the supplement “have been present in the food supply as an article used for food in a form in which the food has not been chemically altered.” 

If it is ever finalized, the most recent Draft Guidance may help the dietary supplement industry to better comply with new dietary ingredient notification (NDIN) requirements in the FD&C Act. In an NDIN, the manufacturer or distributor provides supporting information to the FDA that the new dietary ingredient (“NDI”) or dietary supplement will reasonably be expected to be safe—which is where Master Files come in.

The Specifics

An “NDIN Master File” or “Master File” submitted to the FDA contains identity, manufacturing, and/or safety information relating to an NDI, a dietary supplement containing an NDI, or both. As the name suggests, a Master File can be used as a reference for subsequent NDINs submitted to the agency.

To establish a Master File, an applicant should submit—through the FDA Center for Food Safety and Applied Nutrition’s online portal, or by mail—a cover letter with

  • A statement that the information is being submitted as an NDIN Master File;
  • A brief description of the content of the Master File;
  • Name, mailing address, email address, phone number of the owner (and, if desired, of an authorized representative residing in or doing business in the United States);
  • A table of contents;
  • The necessary manufacturing and/or safety information;
  • A list of persons authorized to reference the master file (with contact information) and any limitations on authorization;
  • Applicants should clearly identify information believed to be trade secret/confidential commercial information and explain the basis for this belief. (If there is none, state that as well.)
  • To authorize third parties to reference information from a Master File, an owner/applicant should also provide the FDA with a separate letter of authorization describing the relevant sections authorized (a Model Letter of Authorization is included on page 9 of the Draft Guidance).

Master Files are discretionary and not required. The FDA will conduct a substantive review of an NDIN Master File only when it receives an NDIN that refers to the Master File. The agency will include a list of NDIN Master Files on its website. Updates to Master Files can be made by mail or through the COSM online portal. A closure of a file may be done by email to NDITeam@fda.hhs.gov, or by regular mail if email is not possible.


The Draft Guidance represents the FDA’s current thinking on the topic and is not binding on the agency or the public. Nevertheless, the FDA urges interested parties to comment on the Draft Guidance before it begins work on the final version. Electronic or written comments should be submitted by June 3, 2024 (include Docket No. FDA 2024-D-0706 for “New Dietary Ingredient Notification Master Files for Dietary Supplements.”) Comments will be publicly viewable unless the procedures for Confidential Submissions are followed.

Many in the industry are skeptical that, even when the guidance is finalized, companies will create Master Files, thereby exposing information to competitors. Much like self-affirmed “Generally Recognized as Safe” (GRAS) determinations—another FDA food ingredient regulatory classification—dietary supplement companies may find that it’s more advantageous to keep product information closely held and worry, if at all, about potential regulatory enforcement later. This is especially true given that the FDA stated “there is no presumption that any particular information in the Master File” is exempt from public disclosure—meaning that a competitor could seek the information under a FOIA request and gain access to the Master File contents if the FDA finds that the information is not a trade secret or confidential commercial information.

For additional information about the issues, or if you have any other questions or concerns about new dietary ingredient notification procedures and timelines, please contact one of the authors or the Epstein Becker Green attorney who regularly handles your legal matters.

Epstein Becker Green Staff Attorney Ann W. Parks contributed to the preparation of this post.

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