Medchemexpress, HY-18341A 500mg L-Thyroxine (sodium salt pentahydrate) CAS:6106-07-6 L-Thyroxine sodium salt pentahydrate (Levothyroxine; T4) is a synthetic hormone for the research of hypothyroidism. DIO enzymes convert biologically active thyroid hormone (Triiodothyronine,T3) from L-Thyroxine (T4). Purity:>98% Medchemexpress has over 10000 novel life-science reagents, reference compounds, APIs and natural compounds for laboratory and scientific use. Other quantity can also be offered.