A Working Group of 25 researchers from 12 different nations gathered in Lyon, France, in June 2023 to finalize their assessment of the carcinogenicity of aspartame, methyleugenol, and isoeugenous drugs at the International Agency for Research on Cancer ( IARC ). Based on” limited” evidence for human cancer, aspartame was deemed” possibly carcinogenic to humans” ( Group 2B ). In experimental animals, there was also” limited” mechanistic evidence for cancer. Based on” sufficient” evidence for cancer in experimental animals and” strong” mechanistic evidence, such as studies in humanized mice and supported by studies of the effects on exposed humans, methyleugenol was classified as” probably carcinogenic to humans” ( Group 2A ).