There are no reported side effects associated with Antronex, a supplement intended, according to its manufacturer, Standard Process, to "support the body's normal detoxification mechanisms." However, because nutritional supplements need not be FDA-approved, the safety of Antronex likely has not been confirmed by peer-reviewed research.
The active ingredient in Antronex is yakriton, a fatty bovine liver extract described as the "detoxicating hormone of the liver" by a Japanese medical researcher, Akiro Sato, in 1929. Sato studied the effect of injections of yakriton on rabbits which had undergone daily intraperitoneal injections of ammonium chloride, a salt which, in large doses, would cause convulsions, weakness, starvation, and ultimately death. Sato found that, injected subcutaneously, yakriton served to detoxicate the ammonium chloride and, in further studies, to detoxicate other poisons such as phosphorus and phenol. Moreover, according to Sato, administering yakriton to rabbits in whom tuberculosis had been artificially induced doubled their survival rate.
In the 1960s, yakriton was made available in the United States as Antronex, a supplement claimed to have antihistamine and decongestant properties when taken orally. Reviewers of Antronex on Amazon and other websites claim that the supplement improves their response to allergies and report no negative side effects. However, as in the case of many nutritional supplements, these reports are entirely anecdotal; apparently, neither the efficacy nor the safety of Antronex has been confirmed by clinical trials.