Should we measure T3 in those patients? I don't think so, because we don't have studies. We don't have data. I don't have a study that shows me, oh, yeah, if the patient has low T3, below 110, those are the patients that will benefit from receiving T3. No, that doesn't exist.

We don't have that, and mostly because T3 levels, the assay to measure T3 is not the best assay in the world. It has a lot of variability. So if you measure T3 in the morning, it might be slightly different than in the afternoon or the next day, just because the assay has an intrinsic variability in it.

Also, T3 levels are affected by caloric intake. So if patients are trying to lose weight-- and many of these patients are trying to lose weight-- your T3 levels will be relatively lower. Therefore, I think it's hard to create-- to generate this data, but we definitely need the data. We don't have any data showing that low T3 patients will respond to T3 therapy. Although it makes sense, we don't have those data.

So I don't think we should measure T3, because we would not know what to do with the result. I think that if we excluded everything, the patient is symptomatic, I think it's worth trying combination therapy. Now, when you have to-- all of this has to be done in agreement with the patient. You have to explain.

And now, who are candidates for combination therapy? We should really think of two things. Number one, older patients probably should not be on combination therapy. Patients that have heart conditions probably should not be on combination therapy, just because we are giving T3, and we know T3 accelerates the heart. And T3 might cause some atrial fibrillation.

Even though there is not a lot of data showing that combination therapy causes that-- in fact, there is no data showing that. There's a lot of data showing that combination therapy is safe when given in doses that respect the levels of TSH. So if you maintain the TSH within the normal range, combination therapy is relatively safe. However, still, because we don't have a lot of data, I would think if a patient has atrial fibrillation or some kind of a cardiac arrhythmia, I would not put that patient on combination therapy.