I would also suggest that you test for
Vitamin D, B12 and ferritin. Usually when Free
T3 is low, there is weight
gain. In doing some reading about weight loss, I found this info. "Other endocrine cause of weight loss is cortisol deficiency. This can be tested by doing 8.00 AM serum cortisol level. You need to be investigated for other causes of weight loss such as some chronic infection, diabetes etc." So this points to the possibility of other tests that may be advisable.