Liothyronine-d3 is deuterated labeled Liothyronine (HY-A0070A). Liothyronine is an active form of thyroid hormone. Liothyronine is a potent thyroid hormone receptors TRalpha and TRbeta agonist with Kis of 2.33 nM for hTRalpha and hTRbeta, respectively[1][2][3].