Yet that's not BVO's only trick. Animal studies have strongly implied the compound can slowly build up in our fat tissues. With bromine's potential ability to prevent iodine from doing its all-important work inside the thyroid, health authorities around the world have been suspicious of the emulsifier's risks for decades.

In fact, BVO is already banned in many countries, including India, Japan, and nations of the European Union, and was outlawed in the state of California in October 2022 with legislation due to take effect in 2027.

Yet the FDA has been slow to convince. In the 1950s, the agency regarded the ingredient as generally recognized as safe (GRAS); an official classification afforded items that have either been appropriately tested or – for ingredients in common use prior to 1958 – don't appear to be harmful.