Liothyronine sodium(Tiromel, Cytomel) is a synthetically manufactured prescription thyroid hormone. It specially consists of the Lisomer of the natural thyroid hormone triiodothyronine (T3).Thyroid hormones stimulate basal metabolic rate, and are involved with many cellular functions including protein, fat, and carbohydrate metabolism. Bodybuilders and athletes are attracted to Iiothyronine sodium for its ability to increase metabolism and support the breakdown of body fat. Most often utilized during contest preparation or periods of lIcutting': the drug is usually said to significantly aid in the loss of fat, often on higher levels of caloric intake than would normally be permissive of such fat loss. To this end, the drug is also commonly used in conjunction with other fat loss agents such as human growth hormone or beta agonists.