Thyroid hormone levels for replacement may start at lower doses of 25 to 50mcg. They can gradually be increased up to 150mcg. Even then, several patients continue to experience symptoms.
This is mainly because medication does not reduce the antibodies causing inflammation. So thyroid gland destruction continues.
Another reason is imbalance between T3 and T4 levels. This is because hormone replacement is mainly in the T4 form. Some cases may require added T3 supplementation.