FDA publishes final guidance on NAC, will exercise a policy of enforcement discretion

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The U.S. Food and Drug Administration (FDA) has published its final guidance on N-Acetyl Cysteine (NAC). FDA maintains that NAC is not a dietary supplement, but following a citizen petition from the Natural Products Association (NPA; Washington, D.C.), is considering initiating rulemaking on the ingredient, and will be exercising a policy of enforcement discretion on NAC products.

“FDA recently confirmed NAC’s exclusion from the dietary supplement definition in response to two citizen petitions. However, we are considering initiating rulemaking under section 201(ff)(3)(B) of the FD&C Act 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),” states the guidance. “If, among other considerations, 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.”

FDA is still in the process of conducting a safety review of NAC, but the ingredient has a long history of safe use. The agency’s policy of enforcement discretion will only apply to “lawfully marketed dietary supplements if NAC were not excluded from the definition of ‘dietary supplement’ and that are not otherwise in violation of the FD&C Act.”

The policy will continue unless safety concerns are identified, and until FDA completes notice-and-comment rulemaking that allows NAC to be marketed as a dietary supplement, or the agency denies NPA’s citizen petition’s request for rulemaking. NPA also filed a lawsuit against FDA due to its actions on NAC, requesting “the Court enter a declaratory judgment and a preliminary and permanent injunction under the Administrative Procedure Act and hold unlawful and set aside FDA’s final actions that are arbitrary, capricious, an abuse of discretion, and contrary to law.”

“Citizens petitions and lawsuits are extreme measures and should be the rare exception, not the rule. The industry experienced significant economic harm as a direct result of the Agency’s yearslong and inexplicable delays on NAC, but thankfully our actions held FDA accountable and forced their hand on issuing final guidance,” said Daniel Fabricant, PhD, president and CEO of NPA, in a press release. “We hope this is a teachable moment for the agency and that basic regulatory obligations in the future are handled in the timely and professional manner befitting of the world’s gold standard.”

The Council for Responsible Nutrition (CRN; Washington, D.C.) expressed gratitude at the final enforcement discretion policy, but continues to take issue with FDA's interpretaion of the drug preclusion clause as it pertains to NAC.

"FDA has suggested that it cannot start the rulemaking process under the exclusion to the drug preclusion clause because it is still reviewing the safety of NAC. FDA has had access to safety information provided by stakeholders at the request of FDA for more than six months, and this ingredient has been sold as a dietary supplement for decades without any safety issues being raised. FDA has had ample time to raise any safety concerns; continuing to stall on the rulemaking at this point just harms businesses and consumers," said Meg Olsen, senior vice president and general counsel for CRN, in prepared statement.

"FDA spokespersons have also indicated that rulemaking could take 3 to 5 years – all the more reason why FDA should begin the rulemaking process immediately or provide its reasoning for needing additional safety or other data," Olsen continued. "We strongly encourage FDA to explore ways in which rulemaking can be expedited, such as using interim rulemaking authority and providing adequate agency resources to the notice and comment rulemaking process so a final rule can be implemented as quickly as the law allows, without the need for additional extensions or delays by the agency during the rulemaking process."