thyroxin

/TH AY1 R AA1 K S IH0 N/
noun
  1. 1

    A hormone (an iodine derivative of tyrosine), produced by the thyroid gland, that regulates cell metabolism and growth.

Source: https://en.wiktionary.org/wiki/thyroxin, https://en.wiktionary.org/wiki/thyroxine