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Thyroid Hormone
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What exactly is Thyroid Hormone Treatment?

One question I am most frequently asked is, “What thyroid tests do I need to assess my thyroid’s function?” This, along with what the thyroid test results mean, are two of the most important topics to understand to determine if you truly have thyroid dysfunction or not. There is quite a lot of misinformation on the internet and in the medical world surrounding thyroid tests, thyroid test results, thyroid medication and treatment. 

Below, I am going to break it down for you so you understand what options you have and so you better understand what may be happening in your own body and how best to approach treatment to be your own best healthcare advocate 

Types of Thyroid Hormone Tests & Optimal Thyroid Levels 

Many doctors only check their Thyroid Stimulating Hormone (TSH) test levels, which indicates if the patient has hypo- or hyperthyroidism. If you’re lucky, a doctor will test their Free T4 levels to see if they are low on the storage form of thyroid hormones. While these thyroid test results do a good job to uncover the nature of a patient’s disease, they only tell you a small part of the story.

 

Normal vs Optimal Thyroid Levels 

If your thyroid test results indicate “normal” TSH test levels– i.e. your TSH falls within the normal reference range used by most conventional doctors and recognized by the American Thyroid Association — it could indicate that you do not have thyroid dysfunction. However, “normal” and “optimal” levels mean very different things. If you still have symptoms and are in the “normal” range rather than “optimal” TSH test levels in your thyroid test results, then you may have thyroid dysfunction, such as subclinical hypothyroidism. 

What is TSH, or Thyroid Stimulating Hormone? 

The hypothalamus is responsible for many things including: managing hunger, thirst, sleep, hormones, and body temperature (among other functions). It also monitors the level of thyroid hormones present in your bloodstream. If it determines that energy levels are low, it sends out TRH, Thyroid Releasing Hormone, to your pituitary gland. 

Your pituitary gland then releases TSH, or Thyroid Stimulating Hormone. TSH is sent directly to your thyroid to produce more T4, the storage form of thyroid hormone. Your TSH level tells you what your pituitary gland is doing based on your hypothalamus’ feedback loop, rather than how your thyroid is actually functioning. 

TSH Thyroid Test Result 

     

- If your TSH test level is high in your thyroid test results, this can be a sign that you are under-producing thyroid hormones and you are hypothyroid. 

     

- If your TSH test level is low in your thyroid test results, this can be a sign that you are over-producing thyroid hormones and are hyperthyroid. It could also mean you are on too much supplemental thyroid hormone. Supplemental T3 or natural desiccated thyroid hormone with T3 can artificially suppress your TSH levels. However, if you don’t have symptoms, it could be perfectly fine if the level appears low. 

What is T4, or the Storage Form of Thyroid Hormone? 

Once TSH signals your thyroid to ramp up the production of its hormones, it produces the four different types of thyroid hormone: T1, T2, T3, and T4. The primary output of your thyroid is T4, which is a storage form of the hormone. It circulates throughout the body and stays in the tissues so that it’s available when needed. I like to measure Free T4 (FT4) since it is unbound and able to act in the body. 

- If your Free T4 level is high in your thyroid test results, it can indicate an overactive thyroid or hyperthyroidism. 

- If your Free T4 is low in your thyroid test results, it can indicate an under-active thyroid or central hypothyroidism. 

What is Free T3? 

When each local area of your body determines that it needs more power, it converts storage T4 into Free T3, which is the active form of the hormone. These hormones attach to receptors inside of your cells to power your metabolic processes. It gives ou “go power”. 

 

- If your Free T3 level is high in your thyroid test results, it indicates that your thyroid is overactive or hyperthyroidism. 

- If your Free T3 is low in your thyroid test results, you may not be converting T4 to Free T3 very well and you could have hypothyroid symptoms even if your TSH level and Free T4 level are within the “normal” range in thyroid test results. This is one of the most common causes of low thyroid or hypothyroidism that I saw in my clinic. 

What is Reverse T3?

Your body also uses a portion of the T4 to create Reverse T3 or RT3, another inactive form of thyroid hormone. This one can attach to the receptors for Free T3 in order to slow down your metabolic processes. 

- If RT3 is high – you are likely converting too much T4 to RT3 and not enough to FT3, which can cause hypothyroid symptoms even if your TSH and T4 levels are optimal. 

What are Thyroid Antibodies? 

A large majority of thyroid conditions are autoimmune, which means your immune system is attacking your thyroid. The hypothyroid form of autoimmune thyroid disorder is Hashimoto’s, and the hyperthyroid form is called Graves’ disease. 

What Thyroid Tests could give the most information about your thyroid condition? 

Most doctors only check your Thyroid Stimulating Hormone (TSH) levels and Free T4 levels.. However, as we’ve just covered, optimal thyroid function involves many factors. Those two levels of thyroid test results alone don’t give us the whole picture. I prefer the following tests: 

- TSH 

- Free T4 

- Free T3 

- Reverse T3 

- Thyroid Peroxidase Antibodies (TPOAb) 

- Thyroglobulin Antibodies (TgAb) 

 

The Optimal Thyroid Levels 

Even if your doctor does order a complete thyroid function test panel, they’re usually relying on “normal” thyroid test results reference ranges that are too broad and often 

inaccurate. When lab reference ranges for a healthy thyroid were created, it was later discovered that people who already had thyroid dysfunction were included in those ranges! 

Because of this, in 2003, the American Association of Clinical Endocrinologists recommended that the lab reference ranges for thyroid test results become more narrow. Yet still today, most doctors and laboratories haven’t updated their practices for optimal thyroid levels. 

I believe the most optimal thyroid levels are: 

- TSH levels of 1-2 UIU/ML or lower 

- FT4 levels >1.1 NG/DL 

- FT3 levels > 3.2 PG/ML 

- RT3 levels < 10:1 ratio RT3:FT3 

- TPO – TgAb levels < 4 IU/ML or negative 

 

If you are undergoing thyroid treatment and are still experiencing symptoms of hypothyroidism it may be time for a more comprehensive evaluation and treatment plan. 

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