What Is Thyroxine Sodium? L-thyroxine sodium is also known as (2S) -2-amino-3- [4- (4-hydroxy-3,5-diiodo-phenoxy) -3,5-diiodophenyl] propionate, This product is thyroid hormone. IN OTHER LANGUAGES English Čeština Dansk Deutsch Svenska Français Italiano Nederlands Norsk Polski Português Español 日本語 한국어