What is T3?
T3 (triiodothyronine) is one of the two main
hormones produced by the thyroid gland,
the other being T4 (thyroxine).
While T4 is the inactive form, T3 is the active
hormone that directly affects nearly every
cell in the body. Approximately 20% of T3
is produced directly by the thyroid gland,
and the remaining 80% is generated by
conversion of T4 into T3 in the liver and
kidneys. T3 influences metabolic rate,
heart and digestive function, muscle control,
brain development, and bone maintenance.
