TSH – Thyroid-Stimulating Hormone

Doctors began using the TSH test in the early 1970’s, before that, Doctors only tested the actual thyroid hormones, T4 and T3.
The Thyroid-stimulating hormone (also known as thyrotropin, thyrotropic hormone, TSH, or hTSH for human TSH) is a pituitary hormone that stimulates the thyroid gland to produce thyroxine (T4), which then converts to triiodothyronine (T3) and to a lesser amount, T1, T2 and calcitonin. The T3 stimulates the metabolism of almost every tissue in the body.

Because the TSH is a pituitary hormone, and not a thyroid hormone, it will not tell us how much the thyroid is actually making in thyroid hormones. It is only telling us the Pituitary gland is telling the thyroid to make hormones in a demanding way because it is needed (high TSH), or it is not telling the thyroid to make hormones (low TSH).

MANY things can happen that will affect TSH levels, making you likely to be not diagnosed properly if that is all that is being tested. To name a few:

• Smoking lowers TSH
• Biotin, (Vitamin B-7), this can lower TSH. To be safe we do not take Biotin 72 hours before testing the thyroid hormones as it can falsely lower TSH but RAISE the Free  T3 and Free T4 results.
• Anti-Convulsant medications lower TSH (these are also used in Manic Depression/Bi-Polar Disorder, another misdiagnosis often made of those with Hashimoto’s).
• Genetic issues with the THRB genes (Thyroid Hormone Resistance Beta), this can cause lowered TSH levels, and the person may be completely bedridden with hypothyroid symptoms.

Being on enough NDT not only removes all the symptoms we had, there are also other things we noticed

• A 3 PM temperature of 98.6 F or 37 C
• A basal temperature at waking, before getting out of bed, of 97.8-98.2 F or 36.5 C – 36.7 C
• A healthy blood pressure and heart rate for our age.
• Improved energy and hunger, because our metabolism is actually working.
• A Free T3 in the top quarter of the lab range and Free T4 in the mid-range area, with a Reverse T3 no more than 2 above the bottom of the lab.

When taking NDT and or T3, our TSH will be suppressed.  This is because these are thyroid hormone REPLACEMENT medications.  This means the Pituitary gland does not need to tell the thyroid to make hormones, because they are being supplied, in full.  A medication suppressed TSH does NOT affect bone or heart health.  It is a TSH that is low or suppressed on NO medications that may cause these issues. The only time the TSH test is really of use, is in the case of being Hypopituitary. This means the pituitary gland itself or the Hypothalamus is diseased, and unable to make TSH. It is also needed for those who have had thyroid cancer and need to keep their TSH fully suppressed.

Some Doctors insist on the TSH test. As long as they run the other actual thyroid tests and KNOW that the TSH will be suppressed on NDT and or T3 medications, you should be fine.

Biotin effects on thyroid testing including TSH:
https://academic.oup.com/ajcp/article/147/suppl_2/S14/3059235