The purpose of this study is to measure the area under the curve (AUC0-48h; extent of systemic availability) and the maxi-mum concentrations (Cmax) of total serum levothyroxine (TT4, bound and free fraction) after a single pharmacological dose of 600 μg administered as tablets also containing iodine supple-ments vs. the same dose of levothyroxine administered as a reference solution without iodine.