Higher cortisol levels reduce TSH (through the effect on the hypothalamic-pituitary system), and this reduces T4 to T3 conversion. Lower cortisol levels increase TSH. resulting in an increase in T4 to T3 conversion. Studies have found that in severe cortisol deficiency, the TSH and FT3 are often high. Cortisol (HC) supplementation in these people, normalises the TSH and FT3.
Many guidelines strongly caution against the risk associated with low TSH. Some doctors and thyroid patients have jumped to the conclusion that a low TSH “causes” osteoporosis. Some even believe a low TSH must be avoided at all costs during thyroid therapy, even if lowering their thyroid hormone dose causes chronic hypothyroid symptoms in a patient!
But as of 2019, the truth is that real science still indicates that suppressed TSH is not responsible for any harm to bones.
I wrote about this first in 2011 when the 'Recovering with T3' book was first released. I thought it was an insightful idea then. Now it is even more important, as we seem to have moved further away from a patient-focused approach.
This short article is about how doctors and endocrinologists measure their own success and how they are assessed by their peers and bosses.