LIOTHYRONINE SODIUM or T3 is a thyroid hormone that greatly affects the basil metabolic rate in a stimulating sense.This hormone is involved in many cellular functions including the metabolism of carbohydrates, fat and proteins. When an individual is no longer producing enough of this hormone on his own, the metabolism does not function properly. By supplementing with T3, this provides the body with the thyroid hormone and it should return the metabolism back to proper working order.