In this 2016 randomized, controlled prospective study of 192 adults with autoimmune thyroiditis, patients were given either 83 mcg SeMet daily or no treatment for four months. At the end of the study, 31.3% of patients in the SeMet group had restored euthyroidism (TSH <4.5mUI/L) compared to 3.1% of patients in the control group.
Pirola, I., Gandossi, E., Agosti, B., Delbarba, A., & Cappelli, C. (2016). Selenium supplementation could restore euthyroidism in subclinical hypothyroid patients with autoimmune thyroiditis. Endokrynologia Polska, 67(6), 567–571. https://doi.org/10.5603/EP.2016.0064