Tirosint and Synthroid are 2 different brands of T4 medication. Tirosint is a
gelcap, containing only 4 ingredients, which are the active ingredient, levothyroxine, water, gelatin, and glycerin. It's basically, hypoallergenic. As a gelcap, it's dissolved and absorbed better than pill type meds. Tirosint starts off at 13 mcg and goes up to 300 mcg.
Synthroid is the leading brand of pill type thyroid hormone replacement meds.