That's because the thyroid gland and the hormones it produces are affected by many different things!
Here are the facts:
1. The thyroid GLAND cannot produce thyroid hormone if it is removed, attacked, or lacks the key ingredients it needs to make thyroid hormone.
2. Once the thyroid gland makes thyroid hormone, the hormone (T4) has to be TRANSPORTED to cells and CONVERTED into its active form (T3). If transport systems and/or conversion pathways are impaired, none of this will happen.
3. Once activated thyroid hormone (T3) reaches cells, it has to be able to get in to do its thing. If the cell can't see thyroid hormone to let it in, nothing will happen.
4. If there are other hormone imbalances with Estrogen, Testosterone, Progesterone, DHEA, Cortisol, insulin, and other hormones, thyroid hormone WILL NOT WORK PROPERLY. All of the hormones affect each other.
5. If you have an unhealthy gut, then the thyroid gland will not have adequate amounts of vitamins, minerals, and amino acids to properly produce thyroid hormone.
6. If you surround yourself with foods and environmental toxins that expose you to Chloride, Fluoride, and Bromide, then you will develop a relative Iodine/Iodide deficiency which will impair thyroid hormone production.
....and the list goes on and on...
HORMONES ARE COMPLICATED, and just giving thyroid medication is never the solution, even if thyroid medication is necessary.
THE COMPLETE SOLUTION is to identify and correct underlying causes and work with someone who is an expert and understanding complex hormone relationships so that your THYROID HORMONE and all other hormones work optimally!