Og her http://www.sciencedaily.com/releases...0315230910.htm
"The study found that patients with very high (>4.0mU/l) or suppressed (≤0.03mU/l) TSH levels more frequently suffered from heart disease, abnormal heartbeat patterns and bone fractures compared to patients whose TSH levels are in the normal range (0.4-4.0 mU/l). Patients who had a slightly low TSH level (0.04-0.4mU/l) did not have an increased risk of contracting any of these conditions.

These results show for the first time that it may be safe for patients taking long-term thyroxine replacement therapy to have a low but not suppressed TSH level. These patients do not show an increased risk of suffering from heart disease, bone fractures or abnormal heartbeat patterns. This means that patients may be able to take slightly higher doses of thyroxine than are currently recommended without having an adverse effect on their health."

Nielsigne