NPA files petition asking FDA to rule NAC as legal ingredient

By Hank Schultz

- Last updated on GMT

©Getty Images - Ildo Frazao
©Getty Images - Ildo Frazao

Related tags NAC regulations

The Natural Products Association has filed a citizen’s petition asking FDA to acknowledge NAC as a legal dietary ingredient. The molecule, which has been on the market for decades, was ruled last year as violative by the Agency.

Barring that, the petition requests that Xavier Barrera, US Secretary of Health and Human Services (HHS) issue a regulation that would make NAC legal.

NAC (N-acetyl-L-cysteine) is a derivative of the amino acid L-cysteine and is a precursor of the cellular antioxidant glutathione. The ingredient was first approved as an inhaled mucolytic drug in 1963. At present it is used in emergency rooms as a treatment in cases of acetaminophen poisoning to prevent severe liver damage. 

Huge market presence

Despite its early use as a respiratory medication, the ingredient has been widely used for many years in finished dietary supplements, frequently as a standalone product. A search of the Dietary Supplement Label Database​ from the NIH’s Office of Dietary Supplements yields 1,442 products containing NAC, including some of the biggest brands in the industry (database accessed August 21, 2021). 

Just last year, food and nutrition giant Nestlé launched its Celltrient range​, with one of those products featuring NAC as a central ingredient. 

According to data provided by SPINS to NutraIngredients-USA​, sales of NAC-containing products grow year-on-year, with combined sales of supplements* in the Conventional Multi-Outlet Channel** and Natural Channel totaling $5.68 million in 2020, a 32% increase from $4.31 million in 2019. 

Race to market Catch 22 

FDA was surely aware of the ingredient being on the market in supplement form for decades, but took no action regarding its status until the summer of 2020 when the Agency sent seven warning letters to companies making hangover treatment claims​ , which FDA construed to be illegal disease treatment claims. 

In those warning letters, the Agency added language indicating that NAC was an illegal dietary ingredient because of  its prior investigation as a drug. This concern with the dates when certain milestones were passed in the development history of an ingredient has come to be known informally as the ‘race to market’ clause.

The NPA petition raises the issue of the Catch 22-type position that supplement product developers find themselves in with this retroactive ruling.  Prior to the passage of DSHEA ingredient developers did not need to concern themselves with making sure they were ‘first.’

“Essentially, the distributor of what was a legal ingredient, pre DSHEA, could be forced off the market because of losing a race-to-market that did not exist when they first placed the ingredient into commerce,”​ the petition states.

In addition, the petition, which was signed by NPA president and CEO Daniel Fabricant, PhD, said reliable evidence exists that NAC was on the market as a supplement prior to 1993, well in advance of the Old Dietary Ingredient grandfather date of Oct. 15, 1994. 

No safety concerns

And, bottom line, Fabricant said ingredients have co existed in drugs and in supplements for decades.  Examples include l-carnitine and caffeine.  NAC, like those two ingredients, has a good safety record.  Nevertheless, the FDA enforcement action has induced Amazon to prohibit the sale of the ingredient on its platforms, which lends some urgency to the resolution of the matter.

“They’re going after an ingredient that they don’t have a safety signal on,”​ Fabricant said.

“Not only has NAC been used safely in products pre-DSHEA, but it is also a common amino acid that’s found in 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,”​ he added.

Petition joins Senator’s letter, CRN petition

Fabricant noted that the NPA petition comes at the same time as a letter on NAC sent by Sen. Mike Lee, R-UT to FDA requesting a public hearing on the use of NAC in supplements. More pressure has been brought to bear by a citizens petition filed by the Council for Responsible Nutrition​ with FDA in June.


* This covers products in the following categories: Amino acid, digestive aids & enzymes, herbal formulas, miscellaneous supplements, performance nutrition, vitamins & minerals 

** The Conventional Multi-Outlet Channel (powered by IRI) covers the Grocery Outlet (store with $2M+ annual ACV), the Drug Outlet (chains and independent stores, excluding Rx sales), and selected retailers across Mass Merchandisers, including Walmart, Club, Dollar, and Military representing over 105,000 retail locations. 

SPINS’ Natural Enhanced Channel is composed of full-format stores with $2 million+ in annual sales and 40% or more of UPC coded sales from natural/organic/specialty products . It Includes co-ops, associations, independents, and large regional chains (excludes Whole Foods & Trader Joes) .

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