TSH Levels Explained

TSH Levels stands for ‘Thyroid Stimulating Hormone Levels’, and for anyone suffering with thyroid problems such as hyperthyroidism (an over active thyroid) or hypothyroidism (an under active thyroid), understanding precisely what these are and how they work is very useful for understanding their condition. However this is not always easy as there is quite a lot of conflicting information out there and it is quite a confusing subject in general. Here we will examine what TSH Levels are, and how they affect your health and thyroid – all in plain old English so that you can understand what you need to know.

What Your Thyroid Does

Before we can examine what TSH levels do, we should look first at what your thyroid itself does and how it interacts with your overall health. The thyroid is a gland that resembles a butterfly in shape that is positioned low down at the front of the neck below the Adam’s apple on the wind pipe. You shouldn’t be able to feel this, though in some cases when the gland becomes swollen you can.

The job of your thyroid is to regulate your metabolism. If you’ve ever heard any one referring to having a slow metabolism (lethargic, overweight) or a fast metabolism (hyperactive, underweight, goes to the toilet a lot) then you will know what this means. Essentially your thyroid is in charge of your metabolism and your anabolism and this means that it both builds tissue and burns fat and glucose for energy. In other words it regulates every cell in the body to do its job in producing and using energy, and in rebuilding the damaged tissue around the body. This has many other impacts on the body, such as controlling your body temperature, your weight, your heart rate and more.

If you take stimulants such as caffeine or the thermogenics marketed for weight loss, then these work by speeding up aspects of your metabolism (the catabolic aspect) and thereby burning more fat, providing you with more energy, increasing your heart rate and raising your body temperature. As you can imagine having too fast a metabolism (hyperthyroidism) isn’t a good thing as you will constantly burn yourself out and be left tired and lethargic, but having too slow a metabolism meanwhile will leave you feeling exhausted and tired as a result of your body not using the energy in your food and in your fat stores, so this will mean you end up gaining weight too.

The other aspect of your metabolism is anabolism, which bodybuilders or athletes might artificially (and illegally) stimulate with anabolic steroids. These steroids cause you to build more muscle, heal and repair wounds, and to feel a powerful drive and determination. If your thyroid isn’t doing this for you then and is under-active, then you’ll also find that you get dry hair and skin, that wounds take a long time to heal and that you feel a lack of drive and determination.

How does your thyroid regulate all this? By producing hormones which we know as T4 and T3. An overactive thyroid produces too much of these, and an under active one doesn’t produce enough.

How TSH Levels Work

The job of TSH levels then is to stimulate the thyroid in order to produce T3 and T4. If you don’t have enough of these TS hormones then, that means that your thyroid won’t produce the T3 and T4 and consequently your metabolism will drop. Too much of them meanwhile and you’ll burn up. So where do these TS hormones come from? Well they too are produced by a gland, this time the ‘pituitary gland’ which is tasked with the job of telling the thyroid when to work.

In other words then there is another potential cause for an under active or overactive thyroid other than simply having a damaged thyroid – it can also be a result of an incorrectly functioning pituitary gland. Many people will overlook this possibility and immediately jump to the conclusion that they have thyroid problems and not think of this alternative problem.

Diagnosing TSH Levels

However some doctors will cotton on to the fact that the fact that the pituitary gland is responsible. While diagnosing your thyroid problems they will look at the thyroid gland for enlargement, will test the heart rate and blood pressure, and will also try to ascertain the functionality of the pituitary gland.

One way they will achieve this is by testing the amount of TSH in the blood by doing a blood test. TSH levels in the body are used to tell the thyroid when it needs to act more and when it needs to act less. So if there are very high amounts of TSH in the blood this suggests that the thyroid is under active – because the body has had to produce a lot of TSH in order to get the thyroid to jump into action. Meanwhile very low amounts of TSH suggest an overactive thyroid. In other words, the pituitary gland tries to compensate for the over-or-under activity of the thyroid by producing more TSH, and so it can be used as an indicator of the thyroid.


So how is this treated? Well for hypothyroidism the pill used is levothyroxine which will attempt to balance the production out again. Doctors may also prescribe T3 and T4 directly in order to compensate for the low production of these hormones by the thyroid. The latter is of course more suited to cases of thyroid problems where the cause is not the TSH levels.

For hyperthyroidism on the other hand, drugs are used that can block T3 and T4 such as methimazole or propylthiouracil, or radioactive iodine treatment will be used in order to actually destroy some thyroid cells to prevent it from overproduction.

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