Cytomel is a thyroid hormone designed and developed to treat hypothyroidism. Hypothyroidism is simply a condition where adequate thyroid hormone(s) are not being produced; commonly this can be caused by an iodine deficiency, as well as pituitary malfunction among other causes but it is a condition that is quite common. Through the use of Cytomel we can increase the amount of thyroid hormones we have in our body, most notably the Triiodothyronine hormone commonly known as T3. The Triiodothyronine hormone is responsible for many functions, most notably metabolic activity but it also plays a role in bodily growth and the heart among many others. As T3 is produced by the pituitary gland its mode of action in terms of development and release is regulated by the thyroid-stimulating hormone (TSH.) Once thyroid hormones both T3 and T4 reach a certain level in the blood production is decreased as increased levels block TSH from being released; however, once the levels fall TSH is again released and more T3 and T4 is produced. By supplementing with Cytomel we actively increase the amount of T3 in our body far beyond what natural TSH will allow.