Hypothyroidism is characterized by elevated thyroid stimulating hormone (TSH) levels. When someone has an “overt” case of hypothyroidism, in addition to the TSH being high, the thyroid hormone levels will be low. Many people have subclinical hypothyroidism, and this is when the TSH is elevated, but the thyroid hormone levels are fine. Regardless of what type of thyroid condition someone has, the goal is to do more than just to lower the TSH. In fact, one can argue that in most cases, the TSH is one of the least important markers to look at, although many medical doctors still rely on this alone. But with that being said, when someone follows a natural treatment protocol we do want the TSH to eventually normalize.
Before talking about some of the reasons why your TSH levels might remain high, even after receiving conventional or medical treatment, it’s important to understand that you can’t rely on the lab reference range. In other words, many times the TSH is within the lab reference range, but is outside of the functional reference range. For example, Labcorp currently uses a reference range of 0.40 to 4.50 mIU/L. However, many consider anything over 3.0 to be too high, and most natural healthcare professionals prefer the TSH to be between 1.0 and 2.0.
So with that being said, let’s go ahead and discuss seven reasons why your TSH might still be high:
Reason #1: Your thyroid antibodies are still high. Most people with hypothyroidism have Hashimoto’s Thyroiditis, which is an autoimmune condition that involves the immune system attacking the thyroid gland. This damage is what leads to the decreased production of thyroid hormone, and this in turn causes the TSH to increase. As I mentioned in the opening paragraph, sometimes the thyroid hormone levels will be within the lab reference range, even when the TSH is high. In fact, most people with Hashimoto’s don’t even know they have this condition initially, as what frequently happens is that their TSH levels will be tested and are on the high side, and then the thyroid peroxidase (TPO) and/or thyroglobulin antibodies are eventually tested, and when the TSH is elevated and one or both of these autoantibodies are elevated this is what leads to the diagnosis of Hashimoto’s Thyroiditis.
There is thought to be a 3-legged stool of autoimmunity, which includes 1) a genetic component, 2) an environmental trigger, and 3) a leaky gut. When someone has Hashimoto’s Thyroiditis, or any other autoimmune condition, there of course is nothing they can do to change their genes. However, this doesn’t mean that you can’t reverse the autoimmune component by detecting and removing the trigger, along with healing the gut. This admittedly can be challenging to do, but it is possible for those who are willing to take responsibility for their health. And when the elevated TSH is caused by the autoimmune component of Hashimoto’s Thyroiditis, the only way to lower the TSH is by reversing the autoimmune component, or by taking thyroid hormone medication.
Reason #2: Problems converting T4 into T3. On a thyroid panel this might present as a high TSH, normal T4, and low T3. And the reverse T3 is commonly on the high side, although not always. As for why someone might have a conversion problem, there can be numerous reasons. Some of the different factors which can affect the conversion of T4 into T3 include a selenium deficiency, liver problems, gut dysbiosis, stress, certain medications, and even inflammation. I discussed these factors in greater detail in a blog post I wrote entitled “6 Factors Which Can Affect The Conversion Of T4 To T3 [1]”.
Reason #3: One or more nutrients important for the production of thyroid hormone are deficient. These include iodine, tyrosine, and iron. As a result, if someone has one of these nutrient deficiencies then this can lead to decreased production of thyroid hormone, which in turn will cause an elevated TSH.
Reason #4: Environmental Toxins. There are tens of thousands of chemicals in our environment, and unfortunately we don’t know the short and long term impact of all of these on our health. But we do know that certain environmental toxins act as endocrine disruptors, including bisphenol A (BPA) and flame retardants. Other toxins which can inhibit thyroid hormone production and thus lead to an elevated TSH include bromide, fluoride, perchlorate, and even heavy metals such as mercury. And while you can’t completely avoid these and other chemicals, you can do things to minimize your exposure to them.
This is especially true in your own home, as you can try to purchase mostly organic food, and use natural products. You can also invest in a water purification system which also helps to minimize your exposure to these toxins. And in addition to reducing your exposure to these chemicals, you can also support your detoxification pathways by eating an abundance of green vegetables, eating garlic, drinking plenty of water, along with some green tea, and perhaps even taking some supplements on an occasional basis to help with the elimination of toxins, such as N-acetylcysteine.
Reason #5: Thyroid hormone resistance. When someone has thyroid hormone resistance the TSH will usually be normal or elevated, and the thyroid hormone levels are also frequently elevated. This isn’t too common, and sometimes it will confuse medical doctors, as when the TSH is elevated it is typical to see the thyroid hormone levels on the low side. This is similar to insulin resistance, which is when the cells are no longer responsive to insulin. With thyroid hormone resistance, the thyroid cell receptors aren’t as responsive to thyroid hormone. As a result, the thyroid hormone levels build up in the circulation, but because the body isn’t utilizing thyroid hormone the pituitary gland looks at this as if it were a thyroid hormone deficiency, and thus will continue to secrete TSH, which in turn signals the thyroid gland to secrete more thyroid hormone. For more information on this condition I would check out my blog post entitled “Thyroid Resistance and Natural Treatment Solutions [2]”.
Reason #6: Dysregulation of the Hypothalamic-Pituitary-Thyroid (HPT) Axis. Remember that thyroid stimulating hormone is secreted by the pituitary gland, and not the thyroid gland. Under normal circumstances the hypothalamus communicates with the pituitary gland through thyrotropin releasing hormone (TRH), and the pituitary gland will secrete TSH, which will signal the thyroid gland to produce thyroid hormone. However, if there is miscommunication between the hypothalamus and pituitary gland then this can lead to an elevation of the TSH levels, even if the thyroid gland is perfectly healthy. Unfortunately this isn’t something that is easily measured, and so it can be challenging to know if someone has HPT axis dysregulation.
Reason #7: Pituitary Tumor. Fortunately this is rare, but some people have a TSH-secreting adenoma, also known as a thyrotropinoma. This is usually benign, and like thyroid hormone resistance, the patient usually presents with an elevated TSH, along with elevated thyroid hormone levels. The TSH secretion by thyrotropinomas shares many characteristics of other pituitary hormone-secreting adenomas, such as abnormalities in growth hormone and/or prolactin (1) [3].
In summary, there are numerous factors which can cause elevated TSH levels. Seven common reasons include 1) the immune system attacking the thyroid gland, 2) problems converting T4 into T3, 3) having a deficiency of iodine, tyrosine, or iron, 4) exposure to certain environmental toxins, 5) thyroid hormone resistance, 6) HPT axis dysregulation, and 7) having a TSH-secreting adenoma. So the obvious goal should be to find out what’s causing the elevated TSH, and then to try to address the cause. However, while it of course is desirable to have a normal TSH, it’s also important to understand that other markers can be even more important to look at, and therefore one should never just test the TSH alone.