This will be a single-center, open-label, two-period, two-treatment, two-sequence, randomized, single-dose, crossover study. 26 healthy adult males will be randomized to receive a single dose (6 x 100mcg tablets = 600mcg) of the test formulation of levothyroxine and reference formulation of levothyroxine separately in each treatment period. There will be two treatment sequences (AB, BA) and a 35 day washout between the two treatment periods.