A Study of Selenomethionine and Myo-inositol(SOLOWAYS_TM) in Patients With Autoimmune Thyroiditis Carrying the DIO2 Thr92Ala Polymorphism

Inclusion Criteria: * Adults aged 18-65 years with a clinical diagnosis of autoimmune thyroiditis (elevated anti- TPO and/or anti-Tg). * TSH range consistent with subclinical hypothyroidism (e.g., TSH 4.5-10 mIU/L) or euthyroid status with AIT; patients on stable levothyroxine therapy are eligible if dose was unchanged for at least 6 weeks. * Willingness to undergo genotyping for the DIO2 Thr92Ala variant. Confirmation of the Thr92Ala variant (homozygous or heterozygous) for Cohort A; absence of this variant for Cohort B. * Ability to provide informed consent and comply with study procedures. Exclusion Criteria: * Overt hypothyroidism with TSH \>10 mIU/L requiring immediate treatment adjustment. * Significant comorbidities (e.g., uncompensated heart failure, severe renal or hepatic dysfunction, uncontrolled diabetes). * Pregnancy or lactation (given potential changes in thyroid requirements and supplement safety considerations). * Known hypersensitivity to selenium or inositol supplements. * Severe psychiatric disorder interfering with protocol adherence. * Concurrent use of high-dose selenium (\>50 µg/day) or other thyroid-influencing nutraceuticals that cannot be discontinued prior to study entry.