Less than 0.05% of Total Thyroxine (T4) is free or unbound. The hormone is made in the thyroid gland and is the precursor to T3. Production of T4 is dependent on levels of iodine, co factors like B6, Biopterin, Copper, Zinc, Vitamins B2, B3 and A. Considered by mainstream when combined with TSH to be the gold standard for assessing thyroid function., Levels are assessed to identify thyroid status (hypo and hyper), Iodine sufficiency as well as protein status and liver function.
Liver & Gallbladder
Minerals & Metals