Confused regulatory position of hordenine, octopamine figures into warning letter

29-Sep-2022 - Last updated on 29-Sep-2022 at 17:24 GMT

Hordenine and octopamine are mentioned as natural constituents of Citrus aurantium, or bitter orange. But the possibility that synthetic versions of these chemicals are being used in dietary supplements is a concern for FDA. ©Getty Images - Matthias Rabbione

Hordenine and octopamine—ingredients of concern for FDA—made another appearance in a warning letter sent to a New York-based supplement manufacturer.

The recent warning letter was sent by the US Food and Drug Administration to Muscle Sports Products LLC, based in Ronkonkoma, NY. The warning letter focused on impermissible disease claims the company was making on a host of supplements, and arose as part of separate website reviews done in May and September 2022. The warning letter was dated Sept. 23, 2022.

The body of the warning letter addresses numerous allegedly non compliant disease claims the company was making on a wide variety of products. Among those claims were:

“With all the concern about the #coronavirus make sure your immune system is #optituned with Immunity + by Optitune!”
“Has been noted to have powerful reductions in anxiety.”
“Has been noted to reduce psychosis.”

Specific mention of hordenine, octopamine content

Further down in the latter, however, FDA voiced concern over the composition of a particular product called RECOMP. This product listed a bitter orange extract (Citrus aurantium) on the label. According to the warning letter, a website page for the product said, “Bitter orange extract contains neuroactive agents, synephrine, hordenine, and octopamine.”

These are in fact constituents of bitter orange extract, but FDA in the past has voiced concern whether bitter orange extracts on the market contain these chemicals in their natural forms and concentration levels or whether they have been spiked with additional synthetic versions. A study FDA did in 2020, that validated analytical methods to look for such synthetic augmentation, found wide variability in the contents of bitter orange extracts for sale on the market, including some that had far more of these amines than would be expected from a natural extract.

Confused regulatory position

To add to the confusion, the regulatory position of hordenine and octopamine is somewhat unclear. In the latest version of FDA’s Ingredient Advisory List these two ingredients and several others have been mentioned as having been removed. In warning letters issues in May, however, the Agency said these ingredients are New Dietary Ingredients for which no notification is on file. But the Muscle Sports letter makes no mention of NDI status.

As far as the Muscle Sports product was concerned, FDA had this to say in the warning letter: “Your website does not provide enough information for us to determine whether hordenine and octopamine have been added to RECOMP Capsules as ingredients or are present in trace amounts as components of Bitter Orange Extract. We also do not know whether these compounds are present in their original biogenic form or as synthetically produced salts (e.g., hordenine HCl).”

The product is still listed on a Muscle Sports web page, where the company states it contains fenugreek, berberine, ashwagandha and bitter orange extract. No supplements panel is available, though, because the company the product “is currently being reformulated.”

Muscle Sports and its principal, Jason Mancuso, did not respond to a request for comment before publication of this report, so it is unknown if the product is being reformulated in response to the warning letter or if that process had begun before.