Thyroid Hormones and Thyroid Disease


The thyroid is a little butterfly shaped gland in the front of your neck that releases hormones with so many essential functions.  Your thyroid hormones are essential in regulating your heart rate, body weight, metabolism, temperature, cholesterol, appetite, gut health, metabolism of fats and sugars, nervous system development, sexual function and libido, and much more!  It becomes very easy to see how an abnormality in thyroid function can have dramatic effects on the body.   This thyroid gland releases two types of hormones, T3 & T4.  T3 is the active version produced in smaller quantities by the thyroid, and T4 is the inactive version that is converted into T3 in the body after being released from the thyroid. 



Low levels of T3 & T4 can manifest as fatigue and excessive tiredness, always feeling cold, intolerance to cold temperatures, difficulty concentrating, difficulty remembering things, constipation, weight gain, heavy menstrual cycles in women, and sometimes numbness and tingling.  Worldwide the most common cause of hypothyroidism is iodine deficiency; however, in the western world many foods are iodine fortified and iodine deficiency is very rare.  In the US, the most common cause of hypothyroidism is autoimmune thyroiditis, also called Hashimoto's disease.  In Hashimoto's disease one’s own immune system has attacked the thyroid, causing it to release less thyroid hormones. 


Elevated T3 & T4 levels can manifest with quite the opposite presentation of hypothyroidism.  Hyperthyroid patients will often have nervousness, anxiety, irritability, low grade fever, intolerance to hot temperatures, racing heartbeat & palpitations, weight loss, lighter menstrual cycles in women, tremors and other muscle problems.  Hyperthyroidism can result from Grave’s disease, pituitary gland dysfunction, hypothalamus dysfunction, nodules or cancer in the thyroid, or inflammation of the thyroid. 

The thyroid receives input from the pituitary by a hormone called Thyroid Stimulating Hormone (TSH), which tells the hormone to make more thyroid hormones (T3 & T4).  The pituitary receives input from a part of the brain called the hypothalamus by a hormone called Thyrotropin Releasing Hormone (TRH).  The thyroid hormones (T3 & T4) exert a negative feedback on the hypothalamus and pituitary, causing them to produce less TRH & TSH.  One of the lab markers we often look at when evaluating thyroid is actually TSH.  Because of that negative feedback, when your T3 & T4 are high (hyperthyroid), then those thyroid hormones inhibit the pituitary and your TSH goes down.  When your T3 & T4 hormones are low (hypothyroidism), your pituitary does not get that negative feedback and sends out more TSH to stimulate the thyroid, so your TSH is high.  


What can you do help with my thyroid problem?

First and foremost we begin with an evaluation of your unique signs and symptoms.  Your healthcare provider at Vivify Health & Wellness begins with a carful history of your symptoms and a physical examination.  You may require medication, you may not.   Elevated thyroid levels (hyperthyroidism) often require further investigation and many times are followed by an endocrinologist.  Low thyroid levels (hypothyroidism) can sometimes be managed with nutrition, lifestyle, and modulating the stress response.  However, hypothyroidism often requires thyroid hormone replacement therapy.  Once placed on thyroid hormone therapies, it is typically a treatment you have to do for life.  This ensures you have optimal function of those thyroid hormones that are so important for how your body functions. 


How do you test for low thyroid?

Prevailing theories have been to test principally for TSH as a screen for thyroid disorders.  Because TSH is the hormone the pituitary makes to tell the thyroid to make more hormones, it will be high when the thyroid is low, and TSH will be low when the thyroid is high.  In many cases looking at TSH will be sufficient to diagnose and treat hypo or hyper -thyroidism.  Several problems do arise when only looking at TSH.  Sometimes a person will have hypothyroid symptoms, but TSH is in the normal range and the free T3 is low.  Sometimes the problem isn’t in the TSH, but actually in the conversion of T4 to T3.  Sometimes the problem is not in T3 or T4 at all, but a version of T3 called reverse-T3 inhibiting the action of T3.  To make it even more complicated, we don’t just look at the total T3 & T4, we need to look at the free T3 & T4.  Free T3 & T4 are the hormones in the blood available to be used, whereas total T3 & T4 include all the thyroid hormones available and unavailable.  At Vivify Health & Wellness, we don’t just look at TSH, we look at you and your signs and symptoms, we look at the complexities of several lab tests, and we try to make certain that you get a treatment that is customized to your own unique situation. 

Thyroid Hormone Replacement Therapy.

Many physicians will prescribe a version of T4 called levothyroxine or Synthroid.  Many of our patients prefer a T3 & T4 combination such as is seen in armour thyroid, nature throid, or WP thyroid.  These T3 & T4 combinations are usually a form of dessicated procine thyroid.  Although the majority of the hormones produced by the thyroid are T4, the thyroid naturally produces 20% T3 & 80% T4.  Many of our patients report doing much better with a thyroid hormone replacement therapy that mimics that natural release.  Research has also shown that cognitive performance, mood, and depressive symptoms were improved with combination T3 & T4 versus levothyroxine alone (Bunevicius et al., 2019).  In 1982 Hoang et al. showed that combination therapy caused more weight loss and 50% of people felt better on combination therapy.

Thyroid Therapy at Vivify Health & Wellness

If you are worried you may be having symptoms of thyroid disease or dysfunction, contact us at Vivify today to have your thyroid evaluated.  We will take into account your unique clinical picture, signs and symptoms, and laboratory tests to help customize a treatment plan individualized to you!


  • Bunevičius, R., Kažanavičius, G., Žalinkevičius, R., & Prange Jr, A. J. (1999). Effects of thyroxine as compared with thyroxine plus triiodothyronine in patients with hypothyroidism. , (6), 424-429.

  • Hoang, T. D., Olsen, C. H., Mai, V. Q., Clyde, P. W., & Shakir, M. K. (2013). Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study. , (5), 1982-1990.