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In brief

On 6 March 2023, FDA issued a Dietary Supplement Ingredient Directory (“Directory“). The Directory is hosted on the agency’s website and is intended to help the public quickly find what the FDA has said about a specific ingredient and whether the agency has taken any action with regard to the ingredient. Importantly, the Directory will replace the previous FDA Dietary Supplement Ingredient Advisory List, which listed ingredients identified by the agency as not lawfully marketed in dietary supplements. Manufacturers and retailers can use the Directory as a tool to stay current on recent developments. The Directory will be updated “periodically to reflect new developments” and is not intended as a comprehensive list including all ingredients used in dietary supplements or all actions FDA has taken with respect to particular ingredients.

In more detail

There are a total of 27 ingredients currently listed in the Directory, many of which are subject to previous FDA warning letters. One particularly helpful feature is the ingredients are listed along with other “known names.” A few notable ingredients listed:

  • Cannabidiol (CBD)

The Directory includes links to FDA’s recent actions and communications with regard to CBD.1 Specifically, the most recent action related to CBD was an FDA statement released in January 2023 concluding that CBD is not appropriate for the existing regulatory frameworks for foods and supplements because its use raises various safety concerns, especially with long-term use. The agency announced it would work with Congress to establish a “new way forward.” 

The Directory also includes a link to a webpage with links to several warning letters related to the marketing of CBD.2 These letters alleged that the firms marketed unapproved new drugs that contained CBD. In addition to the potential safety concern, the agency also noted in these warning letters that under section 201(ff)(3)(B) of the Federal Food, Drug, and Cosmetic Act (FFDCA), CBD products are excluded from the dietary supplement definition because FDA is not aware of any evidence that CBD products were marketed in conventional foods or dietary supplements prior to being subject to substantial clinical investigations.

  • N-acetyl-L-cysteine (NAC)

The Directory contains a link to FDA’s guidance document titled “Guidance for Industry: Policy Regarding N-acetyl-L-cysteine,” which states that FDA has determined that NAC is excluded from the dietary supplement definition under section 201(ff)(3)(B)(i) of the FFDCA because NAC was approved as a new drug before it was marketed as a dietary supplement or as a food.3 However, FDA is considering initiating rulemaking to permit the use of NAC in or as a dietary supplement (i.e., to provide by regulation that NAC is not excluded from the definition of dietary supplement).

In the meantime, FDA exercises enforcement discretion with respect to the sale and distribution of certain dietary supplement products that contain NAC. The enforcement discretion policy only applies to products that would be otherwise lawfully marketed dietary supplements if NAC was not excluded from the definition of “dietary supplement.”

  • Kratom (also known as Mitragyna speciosa)

The Directory contains a link to FDA’s current position on kratom, which provides that it is concerned that kratom, which affects the same opioid brain receptors as morphine, appears to have properties that expose users to the risks of addiction, abuse, and dependence.4 FDA is actively evaluating kratom’s safety, and warns consumers not to use any products labeled as containing the botanical substance kratom.

FDA also has two import alerts that list kratom: (1) Import Alert 66-41, which lists unapproved new drugs that present public health and safety risks; and (2) Import Alert 54-15, which lists any dietary supplements or bulk dietary ingredients that are or contain kratom. Under these import alerts, these dietary supplement products can be detained at the border without physical examination.

Key takeaways

  • With the publication of the new Dietary Supplement Ingredient Directory, it is clear that FDA will continue to take enforcement actions against some of those ingredients currently listed and that pose human safety concerns.
  • For some of these listed ingredients, because FDA has made clear that they are not appropriate for use in foods or dietary supplements, companies that market or plan to market these dietary supplements do so at the risk of FDA enforcement. Companies should closely monitor the Directory, and also review product portfolios against the listed ingredients.
  • Companies may also be subject to increased risks of consumer products liability lawsuits for marketing products containing listed ingredients.


For further information and to discuss what this development might mean for you, please get in touch with the Baker McKenzie contacts provided above.

1. FDA Regulation of Cannabis and Cannabis-Derived Products, Including Cannabidiol (CBD) (last accessed 8 March 2023), available here.

2. Warning Letters and Test Results for Cannabidiol-Related Products (last accessed 8 March 2023), available here.

3. See FDA, Guidance for Industry: Policy Regarding N-acetyl-L-cysteine (

4. FDA and Kratom (last accessed March 8, 2023), available here.


Xin Tao is a member of Baker McKenzie's North America Steering Committee for Healthcare & Life Sciences, and currently heads our US Food and Drug Law Practice. A former research biochemist, Xin brings a deep understanding of the complex scientific issues that relate to the US FDA's legal and regulatory requirements, enabling him to help clients with all phases of product development, manufacturing, and marketing. As the science and technology continues to evolve, Xin supports our clients to constantly innovate and push the boundaries of what's possible in the world of life science. Xin is a frequent speaker and writer on US FDA legal developments related to emerging technology, and he has been selected to serve on the 2023 Law360 Life Sciences Editorial Advisory Board.


Genevieve M. Razick is an associate in the Litigation and Government Enforcement Practice Group in the Washington, DC office. Genevieve practices in the area of US Food and Drug Administration and healthcare regulatory and compliance law.

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