Cytomel (T3) is not an anabolic/androgenic steroid but a thyroid hormone. As a substance it contains synthetically manufactured liothyronine sodium which resembles the natural thyroid hormone tricodide-thyronine (L-T3). The thyroid of a healthy person usually produces two hormones, the better known L-thyroxine and the aforementioned L-triiodine-thyronine. Since Cytomel is the synthetic equivalent of the latter hormone, it causes the same processes in the body as if the thyroid were to produce more of the hormone. It is interesting to note that L-T3 is clearly the stronger and more effective of these two hormones.
Bodybuilders take advantage of these characteristics and stimulate their metabolism by taking Cytomel, which causes a faster conversion of carbohydrates, proteins, and fats. Body builders, of course, are especially interested in an increased lipolysis, which means increased fat burning. Competing body builders, in particular, use Cytomel during the weeks before a championship since it helps to maintain an extremely low fat content, without necessitating a hunger diet. Athletes who use low dosages of Cytomel report that by the simultaneous intake of steroids, the steroids become mote effective, most likely as the result of the faster conversion of protein.