From Thyroid.org: Notes March 2004 on “Patients with subclinical thyroid disease have few abnormalities and treatment has no proven benefit”:

The panel concluded that marked (but not mild) subclinical hyperthyroidism is a risk factor for atrial fibrillation (a cardiac rhythm disorder) and low bone density, but that there is insufficient or no evidence to conclude that it is associated with symptoms of hyperthyroidism or cardiac dysfunction, or that these problems can be reversed or prevented by antithyroid therapy.

I like the part about “few abnormalities” but not about “atrial fibrillation and low bone density” not finding any relief when treated with antithyroid therapy. This makes me wonder if the opposite is true: do patients with subclinical hypothyroidism have little or no relief when treated with T4?

Additionally, much of the research I’ve done suggests the ‘establishment’ is slow on the uptake when treating thyroid disorders, but it looks to me like they’re certainly working on it: apparently, the addition of a small amount of T3 does not make many hypothyroid patients feel better.