What we need to keep in mind here, as with all drugs, is variance between individuals. T3 will cause a reduction in body water which is partly accountable for weight loss. T3 is not a direct lipolytic hormone. It speeds all metabolic prcesses in the body including muscle protein degredation. Some people will react unfavorably to this and will experience muscle loss and weakness. This is why I think it is better of utilizing T3 only for that last pound or two of fat that just won't come off at the end of a diet. At the end of dieting is when the body's metabolic rate is at its slowest and then is a oporitune time to increase, exogenously, the metabolic processes of the body.