Thyroid Plus is formulated with essential minerals, vitamins and herbs to support an under-active or sluggish thyroid. Featuring iodine, a key component of T4 and T3 and selenium, a cofactor for converting T4 into the more potent T3, as well as manganese, copper and zinc. Plus, key vitamins like vitamin A, required for activation of thyroid hormone receptors, L-tyrosine, and stress-supporting herbs ashwagandha and bacopa.