Two thyroid hormones – thyroxine (T4) and triiodothyronine (T3) – regulate the body's metabolism of proteins, fats, and carbohydrates, directing how the body uses these compounds to produce energy.* Thyroxine supports cardiac output, heart rate, respiratory rate, and basal metabolic rate.* The thyroid gland cannot produce these two hormones without the presence of the amino acid L-tyrosine and the mineral iodine.* Thus, a deficiency of either the amino acid or the mineral or both can contribute to low thyroid hormone levels.* Thorne's Iodine & Tyrosine offers essential mineral and amino acid support for the thyroid gland.* Studies have found L-tyrosine can be beneficial for treating fatigue, a common symptom of low thyroid or adrenal hormone levels.*

Tyrosine is also an important cofactor for adrenal neurotransmitter synthesis, because it is converted in the adrenal glands into dopamine, norepinephrine, and epinephrine.*

Individuals should be aware that some foods can cause a relative iodine deficiency by binding to iodine, which can make the bound iodine inaccessible for thyroid hormone production. These foods include broccoli, cauliflower, cabbage, Brussels sprouts, kale, soy, peanuts, pine nuts, turnips, and rutabaga, although cooking these foods tends to make them less apt to do this.