Hello, I am trying to give you some more information regarding your problem. At your age the most common cause of hypothyroidism is Hashimoto thyroiditis, an autoimmune disease. It means that your body produces antibodies that destroy the thyroid gland and as a result it doesn t produce enough hormones. At this point you have to take the hormone orally in order to maintain a normal hormonal balance. This is a chronic disease and irreversible. Selenium tablets would be of help if taken during the first phases of the disease (when the antibodies are high but the thyroid hormones are within the normal ranges). Because selenium lowers the antibody titre and the disease would progress more slowly. Once the thyroid gland is destroyed, there is no treatment to return it in the prior situation. So the replacement hormonal therapy should be started and taken long life. I think you can understand now that the treatment you take does not improve the disease but just replaces the damages that it causes. Hope i was clear and helpful. Kind regards, Dr.Mirjeta