What is normal range for tsh levels to vary? 1 or 3 or .5?

Depends: On the assay. Most 3d generation assays fix the bottom # at about 0.3 micro iu/ml. The upper limit is less well defined. Although most assays use about 4-5.5 most of us thyroidologists think it is closer to about 3 microiu/ml.

TSH range: Some scientific studies show that the opitmal range for TSH is 0.8-2.1 in fact a TSH >2.5 is associated with Insulin resistance, as the TSH increases (above 2.5) the LDL goes up and the HDL goes down.

Depends: Some doctors consider 2 to be getting high. But really it is the balance of T3 (liothyronine) to reverse T3 (liothyronine) that matters. T4 is converted to both T3 (liothyronine) and rt3, and T3 (liothyronine) is like the gas while rt3 is like the brakes. Tsh does not reflect this balance and cannot be used in isolation to uncover thyroid problems.