iHerb confirmed on Tuesday it is no longer selling dietary supplements containing the healthy aging ingredient called NMN (nicotinamide mononucleotide) in the U.S.

iHerb joins some other large retailers, including Amazon, in stopping the sale of NMN.

The U.S. Food and Drug Administration in 2022 concluded that NMN is excluded from dietary supplement products because it is the subject of substantial clinical investigations that have been been instituted and made public. Metro International Biotech LLC (Metro) has been investigating the use of NMN to treat medical conditions, including Alzheimer’s disease.

“Given the FDA's restrictions on NMN dietary supplements, these products are no longer available to our U.S.-based customers,” iHerb said in an email to Natural Products Insider.

The move appears to be recent. Four days ago, a consumer said in a Reddit post that he received an email from iHerb noting it planned to discontinue the sale of NMN on Feb. 26. A company spokesperson did not immediately respond to a follow-up question regarding when iHerb stopped selling NMN.

“They didn’t provide an explanation but pushed to buy in bulk,” the post added. "Anyone know why they’d be doing that? Possibly Big Pharma related?”

In November, in a 12-page letter, Metro requested FDA uphold its determination that NMN cannot be lawfully marketed in dietary supplement products.

Related:NMN is precluded in supplements, says pharma company to FDA

Metro submitted the letter in response to a citizen petition filed in 2023 by the Alliance for Natural Health USA and Natural Products Association (NPA). The citizen petition requested FDA reverse its position that NMN is excluded from the definition of a dietary supplement. The agency has not substantively responded to the petition.

About a year ago, Amazon advised sellers they could no longer sell NMN as a supplement. Several NMN brands, however, continue to sell the ingredient in the U.S.

“iHerb taking NMN off its platform is a big deal. It was the last major online retailer to carry NMN,” said an industry source close to the NMN market, who agreed to speak on condition of anonymity due to the sensitivity of the regulatory issues. “First Amazon, then Walmart, and now iHerb. Brands are really getting backed into a corner to supply safe nutritional supplements to their customers. We're now at a pivotal moment for NMN. I hope that brands can work together to find a solution.”

According to industry sources, Walmart also stopped selling NMN supplements, following FDA’s determination. The company did not respond by press time to a request for comment sent through its website.

Related:ChromaDex agrees with FDA on NMN decision