Diiodotyrosine (DIT) is a precursor in the production of thyroid hormone, and results from iodization of monoiodotyrosine at the other meta- position on the phenol ring.
By using supplemental diiodotyrosine, an adequate supply of thyroid’s building blocks can be insured, allowing the user to maintain optimal thyroid levels (as long as other needs are met). This stuff is essentially like a thyroid prohormone, in simplest terms, and as long as your body has adequate levels of the other building blocks and enzymes, it will assist thyroid output.