en Endocrinology Endocrinology Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:14pt"><b><i><span style="color:blue">Background</span></i></b><i><span style="color:blue">:</span></i> The current study intends to assess the impact of oral selenium intake on anti-Tg antibody in individuals with autoimmune hypothyroidism. </span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Methods:</span></i></b> In this double-blinded randomized controlled trial, two groups of 72 autoimmune hypothyroid patients were randomly assigned; One group received levothyroxine (LT4) and oral selenium and the other group was given placebo with LT4. Anti-Tg antibody, free T4, anti-TPO antibody, and TSH were identified in both groups before the treatment and also 3 months after treatment and analysis of data was done by SPSS software.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Results:</span></i></b> After the intervention, the <span lang="EN-CA">average</span> amount of anti-Tg antibody decreased in both of the groups, and this decrease was noticeably greater in the intervention group (P = 0.03). In the intervention group, the TSH level decreased after the intervention (p < 0.05), and the free T4 level increased after the intervention (p < 0.05); the changes in these two variables were statistically significant.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Conclusion</span></i></b><i><span style="color:blue">:</span></i> Consumption of selenium, compared to placebo, in patients with autoimmune hypothyroidism drastically reduces the level of anti-Tg antibody, and it significantly increases the free T4 level. Also, there is a greater decrease in the level of TSH compared to the control group.</span></span></span> Anti-Tg antibody, Selenium, Autoimmune hypothyroidism.idism 340 346 http://caspjim.com/browse.php?a_code=A-10-2468-2&slc_lang=en&sid=1 Mina AkbariRad akbariradm@mums.ac.ir 100319475328460047794 100319475328460047794 No Department of Internal Medicine, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Zahra Mazloum Khorasani MazloumZ@mums.ac.ir 100319475328460047795 100319475328460047795 Yes Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Behnam Beizae beizaeb901@mums.ac.ir 100319475328460047796 100319475328460047796 No Department of Radiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Hossein Ayatollahi ayatollahih@mums.ac.ir 100319475328460047797 100319475328460047797 No Department of Hematology and Blood Banking, Cancer Molecular Pathology Research Center, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran Maryam Emadzadeh emadzadehm@mums.ac.ir 100319475328460047798 100319475328460047798 No Clinical Research Development Unit, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran Mehrdad Sarabi sarabim921@mums.ac.ir 100319475328460047799 100319475328460047799 No Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Nikoo Saeedi nikoosaeedie@gmail.com 100319475328460047800 100319475328460047800 No Student Research Committee, Islamic Azad University, Mashhad Branch, Mashhad, Iran Negar Nekooei nnekooei@yahoo.com 100319475328460047801 100319475328460047801 No Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran