Today, the U.S. Food and Drug Administration (FDA) is announcing the availability of a draft guidance on FDA’s policy regarding products labeled as dietary supplements that contain N-acetyl-L-cysteine (NAC). The draft guidance, when finalized, will explain our intent to exercise enforcement discretion with respect to the sale and distribution of certain NAC-containing products that are labeled as dietary supplements. This enforcement discretion policy would apply to products that would be lawfully marketed dietary supplements if NAC were not excluded from the definition of “dietary supplement” and are not otherwise in violation of the Federal Food, Drug, and Cosmetic Act (FD&C Act).

As we discussed in a recent response to two citizen petitions, the FDA has determined that NAC is excluded from the dietary supplement definition under the FD&C Act because NAC was approved as a new drug before it was marketed as a dietary supplement or as a food. However, we have not yet reached a final decision on one petitioner’s request to issue a regulation to permit the use of NAC in dietary supplements, and we are considering initiating rulemaking to provide by regulation that NAC is not excluded from the definition of dietary supplement. If, among other considerations, the FDA does not identify safety-related concerns as we continue our review of the available data and information, we are likely to propose a rule providing that NAC is not excluded from the definition of dietary supplement.

While our full safety review of NAC remains ongoing, our initial review has not revealed safety concerns with respect to the use of this ingredient in or as a dietary supplement. In addition, NAC-containing products represented as dietary supplements have been sold in the United States for over 30 years and consumers continue to seek access to such products. Accordingly, while the FDA continues its evaluation of the request to initiate rulemaking, the FDA issued this draft guidance to explain our policy regarding products labeled as dietary supplements that contain NAC.

Unless we identify safety-related concerns during our ongoing review, the FDA would intend to exercise enforcement discretion (as described in the draft guidance) until either of the following occurs: we complete notice-and-comment rulemaking to allow the use of NAC in or as a dietary supplement (if we move forward with such proceedings) or we deny the citizen petition’s request for rulemaking. If the FDA determines that this enforcement discretion policy is no longer appropriate, we will notify stakeholders by withdrawing or revising the guidance.

To Submit Comments

To ensure comments about this draft guidance are considered before the FDA begins work on the final guidance, please submit written or electronic comments within 30 days of publication in the Federal Register of the notice announcing the availability of the draft guidance.