The Natural Products Association (NPA) recently filed a citizen petition with the U.S. Food and Drug Administration (FDA) requesting that the agency include N-acetyl-cysteine (NAC) as a dietary supplement ingredient.
 
Currently, the agency precludes this naturally-occurring amino acid from the definition of a dietary supplement due to the fact that it was approved as an inhalant drug in 1963. In the decades prior to FDA’s decision to object to the use of NAC as a dietary supplement ingredient, the agency has not taken enforcement action against companies which marketed NAC as a dietary ingredient, and has considered structure-function claims and at least one qualified health claim for NAC without objecting to the use of it in dietary supplements. However, the agency’s policy change became apparent in 2020 when it issued a series of warning letters as part of its initiative on hangover disease claims to multiple NAC manufacturers who sold it.
 
NPA reports that there were 1,170 dietary supplements containing NAC on the market when the aforementioned warning letters were issued, according to listings on the National Institutes of Health Dietary Supplement Label Database.
 
“The Food and Drug Administration has not established a public health risk for NAC,” Daniel Fabricant, PhD, president and CEO of NPA, said. “Not only has NAC been used safely in products pre-DSHEA [The Dietary Supplements Health and Education Act], but it is also a common amino acid that’s found in the food we eat every day like onions and garlic. We are continuing to tell our members to sell the product directly, and today’s action is another signal to the FDA that we are going to stand up for the industry and consumers’ access to safe and well-regulated supplements.”
 
In the citizen petition, Fabricant states that, like both L-carnitine and caffeine, NAC was marketed as both a dietary ingredient and a drug prior to the passage of DSHEA, which as a piece of legislation include a “race to market” paradigm which indicates that any articles marketed as both drugs and dietary ingredients prior to its passage should be allowed to continue to be marketed as both.
 
Notably, Senator Mike Lee (R-UT) requested in a recent letter that Acting Food and Drug Administrator Janet Woodcock hold a public hearing for the agency to clarify its position on the use of NAC in dietary supplements. He discussed the letter in a video published on July 30.
 
The Council for Responsible Nutrition, another trade association representing the dietary supplements industry, also submitted a similar Citizen Petition to the FDA in June.