IRCT20180510039601N1 IRCT 2018-06-02 Shahid Beheshti University of Medical Sciences selenium in Hashimoto The effects of selenium supplementation on Thyroid gland size in Hashimoto's thyroiditis 2013-04-04 anticipated 60 Complete https://irct.ir/trial/31101 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: individual unit, simple randomization with table of random numbers, Blinding description: in this trial we use selenium and placebo with same package ,color and shape with different cod based on table of random numbers . An endocrinologist is care provider and Outcome assessor of research. He selects participants based on inclusion criteria and then phones to another investigator to determine participant code.then participant refers to one radiologist for thyroid sonography with their cod. after 3 month of treatment sonography and examination repeats and findings is recorded. the end of trial findigs are analysis just with codes. Thus Participent , care provider , outcome assessor and Data analyser are blinded. 2-3 Condition 1: Autoimmune thyroiditis,. Condition 2: Nontoxic goiter, unspecified. Intervention 1: Intervention group: selenium Tablet, 200 micro gram, once daily, per Oral , for three months, From Century 21 company. Intervention 2: Control group: placebo once daily, per Oral , for three months. No - There is not a plan to make this available Justification or reason for not sharing IPD is There is no further information