6-PTU is a thiolated uracil derivativewhich has been shown to acts as an antihyperthyroid agent. 6-Propyl-2-thiouracil is known to inhibit the deiodination of thyroxine to triiodothyronine via deiodinase, iodothyronine, type I (DIO1).It is a thyreostatic (thyroid hormone) agent that may be used as a reference material in thyreostatic drμg separation and detection technologies such as capillary electrophoresis, HPLC, or gas chromatography.