CAS 55-03-8 appears in our catalog under these names: Thyroxine Sodium Salt, >95% (HPLC), L-Thyroxine sodium/ 99.56% (existing batch purity), Levothyroxine sodium, L-Thyroxine (sodium), 99.75%, L-Thyroxine (sodium) (Standard). Offered by: TRC, TargetMol, GLPBio, MedChemExpress. Available pack sizes: 10g, 1g, 25g, 500mg, 100mg, 25mg, 1 g, 10mM/1mL.