The thyroid gland is susceptible to the formation of nodules. Therefore, due to the critical role of selenium in the function of the thyroid gland, the impact of this element on the size and volume of this organ and its nodules were examined.

During three months, two groups consisting of 30 patients with benign thyroid nodules who were referred to Baghaeipour Endocrinology Clinic were given daily doses of 100 and 200 micrograms of selenium, and a control group of 30 people without selenium consumption were assessed.

The results of intergroup analysis detected that the mean (±SD) of nodules length in the 100 µg selenium consumer group was 17.13 (±7.9) and 14.93 (±6.01) before and after intervention respectively (P= 0.008). About the nodules height in the 200 µg selenium consumer group, the mean (±SD) was 9.3 (±2.8) and 8.93 (±2.71) before and after intervention in that order (P= 0.001).

Our findings suggest that selenium has been effective in the size and volume of the nodule and thyroid gland, as well as the TSH hormone, and further studies are needed to determine its therapeutic approach and efficacy.