FDA has already received over 350 comments in response to a draft guidance related to products containing NAC (N-acetyl-L-cysteine) and marketed as dietary supplements.

The public health agency has determined NAC was first approved as a drug in 1963, precluding its use in dietary supplements. In recently published draft guidance, though, FDA said it intends to exercise enforcement discretion regarding products containing the ingredient and labeled as dietary supplements.

FDA requested written comments on its guidance within 30 days of publication in the Federal Register so it could consider the remarks before it begins work on a final document.

Many of the written comments have been submitted by consumers advocating to keep NAC available in products labeled as dietary supplements. George LeBaron is among them.

“NAC has demonstrated a multitude of beneficial effects based on oral administration,” he wrote to FDA. “Most notable is its ability to help support glutathione levels and subsequently attenuate normal oxidative stress.”

LeBaron requested FDA permit NAC “to remain available as a low-cost dietary supplement, which consumers use not as a drug, but as a safe functional method of supporting glutathione levels in their bodies.”

Several commentators made the same request, based on what appears to be a form letter.

One anonymous submission indicated their naturopathic doctor prescribed NAC for sinus infections, which has been helpful to them.

“We will not tolerate the drug industry holding hostage … nutritional supplements,” another person named Tony Pezz wrote to FDA. “That includes the recent effort to convert NAC status from supplement to pharmaceutical so that drug companies can capitalize on it. Keep these financial sharks and their lobbying influence in check.”

Teresa Hunt described NAC as a “staple supplement” for her that’s “affordable and obtainable.”

“Please dont give it away to drug companies to profit from it at my expense,” she wrote.

The Alliance for Natural Health USA submitted comments to FDA on behalf of over 3,400 individuals.

“It is critically important to maintain access to affordable NAC supplements,” the group stated. “Experts say that NAC has shown promising results in people with bipolar disorder, schizophrenia, OCD and addictions. It can also decrease inflammation and may help delay brain atrophy in Alzheimers disease, protects the body from toxins, is a selecive immune system enhancer and helps remove free radicals, which contribute to neurogenerative diseases and aging.”

Warren Stout wrote, “Leave NAC a supplement and focus your efforts on something that needs your attention.”

In March, FDA denied requests by two trade associations that the agency reverse its position that NAC is excluded from the definition of a dietary supplement. FDA, however, is still considering initiating a first-of-its-kind rulemaking that would legalize NAC in dietary supplements.

NAC has long been an ingredient in dietary supplements in the U.S., based on evidence provided to FDA that NAC was marketed in nutritional products before passage of the Dietary Supplement Health and Education Act of 1994 (DSHEA).

Jim Emme is CEO of NOW Health Group, a well-known supplements company that sells NAC. Emme said he was “pleased” yet “not satisfied” with FDA’s draft guidance published last month.

“The guidance recognizes that NAC has thus far been shown to be a safe ingredient during the time it has been sold and marketed as a dietary supplement, which in our opinion is substantiated by few if any adverse event reports for NAC,” Emme said in an email. “We do believe that the agency could have been more conclusive in this matter by recognizing NAC as an old dietary ingredient sold and marketed before DHSEA became law in October of 1994.”