triiodothyronine

/T R AY0 AY1 AH0 D AH0 TH AY1 R AH0 N AY0 N/
noun
  1. 1

    The most powerful thyroid hormone, affecting almost every process in the body, including body temperature, growth, and heart rate.

Source: https://en.wiktionary.org/wiki/triiodothyronine