Thorne Thyrocsin contains key ingredients for thyroid support, including iodine, which is necessary for formation of T4, and L-tyrosine, a necessary component of both T4 and T3 formation.
Thyrocsin also includes several nutrient cofactors necessary for converting T4 to T3, including the minerals selenium, zinc, and copper. Thyrocsin includes vitamin B12 a deficiency of this vitamin appears to interfere with the activity of thyroid hormones. Conversion of T4 to T3 can be inhibited by heavy metal toxicity and lipid peroxidation; hence, the inclusion of antioxidant vitamins C and E to counterbalance this inhibition.
Animal studies have indicated that the Ayurvedic botanical, ashwagandha, can increase T4 concentrations.