Editor's note: For an update on this broader regulatory issue, check out this story published on March 31, 2022.
Amazon confirmed this week it’s in the process of removing from its website dietary supplements containing NAC (N-acetyl-L-cysteine).
FDA last year asserted in warning letters that NAC couldn’t be lawfully marketed in dietary supplements because it was first studied as a drug in 1963. The Council for Responsible Nutrition (CRN) made legal arguments challenging the agency’s position in a 2020 letter to FDA.
The controversy puts an online retail giant like Amazon in a pickle: It must essentially pick a side in the fight between FDA and industry—Either continue to sell NAC-containing supplements and risk FDA enforcement action, or remove the products from its website.
“Third-party sellers are independent businesses and are required to follow all applicable laws, regulations and Amazon policies when listings items for sale in our store,” an Amazon spokesperson said late Wednesday in an emailed statement. “We have proactive measures in place to prevent prohibited products from being listed and we continuously monitor our store. Those who violate our policies are subject to action, including potential removal of their account.”
The spokesperson added, “We are in the process of removing the [NAC-containing dietary supplement] products in question from our store.”
Amazon also owns Whole Foods Market—and at least one trade association head acknowledged he wouldn’t be surprised if Whole Foods also removes NAC from store shelves. Amazon did not immediately respond Thursday to a follow-up question whether those plans were in the works.
“As the mothership goes, so goes Whole Foods,” said Dan Fabricant, Ph.D., president and CEO of the Natural Products Association (NPA).
NPA is advising its members to continue selling NAC-containing supplements. FDA hasn’t taken final agency action on NAC, and there’s been debate on such issues as when NAC came to market as a drug, Fabricant said in an interview.
“Like we’ve told our members, sell it direct,” he added. “Sell it through other vendors because it’s not an unlawful ingredient. This is by no way a closed chapter with FDA on NAC.”
Megan Olsen, vice president and associate general counsel of CRN, said she hasn’t heard that other retailers plan to stop selling NAC-containing supplements, and she believes many traditional brick and mortar retailers are still selling the products.
“CRN has continued to have discussions with both FDA and Amazon regarding this issue,” Olsen said in an interview. “We are very pleased that Amazon is at least continuing to talk with us, though of course they have not committed to …. change their course of action.”
According to Olsen, Amazon has asked brands to remove NAC-containing supplements from its website.
In April, several industry sources told Natural Products Insider that Amazon had started to remove NAC-containing supplements from its platform. At the time, however, several supplements containing the ingredient remained available for sale.
The executive of a supplement brand, who agreed to speak on condition of anonymity, said its NAC products were removed a few weeks ago, subsequently reinstated last week, then removed again this week.
“We still don’t know the full story of ‘why’ on this, other than Amazon seems to have been spooked and, we think, overreacted regarding the pharma patent on NAC,” the industry source said.
In response to questions about NAC-containing supplements sold through another e-commerce giant—eBay—an eBay spokeswoman responded in an email, “We regularly work with the FDA and remove listings for products that have received warnings and/or recalls.”
The eBay spokeswoman did not immediately respond to follow-up questions whether eBay has started to remove NAC-containing supplements from its website. As of late Wednesday, such products remained available for sale on eBay’s website through several different supplement brands.
In a letter to FDA in December, CRN outlined its reasons for why the agency should “revert to its long-standing policy of allowing manufacturers to market products containing NAC as dietary supplements.”
Olsen said FDA acknowledged receipt of the letter but hasn’t substantively responded to it.
“We would implore retailers that it’s not the end of the fight,” she said in an interview in April. That was the same month an FDA spokesperson disclosed the agency had no “updates on its position regarding NAC.”
In a follow-up interview Thursday, Olsen added, “We’ll continue to push with Amazon that FDA is still talking to CRN and has indicated that the letter is still under review with the agency.”
Indeed, on Thursday, FDA's acting director of the Office of Dietary Supplement Programs (ODSP), Cara Welch, Ph.D., sent a brief letter to CRN. Welch divulged FDA officials "are closely reviewing" CRN's 2020 letter regarding NAC "and will provide a more substantive response once our evaluation is complete."
John Troup, Ph.D., vice president of scientific affairs and dietary supplements with the Consumer Healthcare Products Association (CHPA), described the NAC controversy as “a classic example of the need” for talks related to regulatory reform and modernization of the Dietary Supplement Health and Education Act of 1994 (DSHEA).
“NAC is a very important drug, but it also has a long history as a dietary supplement, and FDA’s recent actions left a lot of ambiguity for NAC in the category,” Troup said via email. “It appears that the Center for Drug Evaluation and Research (CDER) is increasingly taking enforcement action in the dietary supplements category around ingredients used in both drugs and supplements.”
He said CDER and ODSP must communicate and collaborate.
"Our hope is that the ODSP will provide clarity, which is essential for both consumers and industry," Troup added.
Fabricant, who previously directed FDA’s Division of Dietary Supplement Programs, questioned FDA’s focus on an ingredient that he said did not pose a risk to public health.
“What’s the public health risk to NAC?” he asked. “There isn’t one. NAC has been used safely pre-DSHEA. It’s a metabolite of an amino acid, an essential amino acid. It’s found in onions and garlic, so this is the hill they (FDA officials) want to die on? I mean if that’s the case, this is going to become obvious to people that all they’re trying to do is protect pharmaceutical IP.”
In a 2020 interview with Natural Products Insider, Steven Tave, then-director of ODSP, said FDA was simply applying the law to facts and not favoring one commodity over another.
“We don’t favor anybody,” Tave, a lawyer now working in FDA’s Office of Regulatory Affairs, said. “We read the law. We look at the facts. We see what the implication of the facts is in the context of the law, and we make our determination.”