The Dangers of Hashimoto's – Part 1 

Written by Anil Bajnath, MD
Posted October 5, 2021

Dear Longevity Insider,

Hashimoto's, also known as Hashimoto's Thyroiditis, is considered to be the most common cause of hypothyroidism. It is an autoimmune disorder that causes your thyroid to produce less than optimal amounts of hormones. The body needs these hormones to regulate its metabolism and other functions. Follow us along as we discuss what Hashimoto’s is and how it relates back to Hypothyroidism.


The thyroid is a small gland in the front of your neck. It releases hormones that affect everything in the body, from heart rate to energy levels. Hormones produced in the thyroid include T3 and T4, two of the most important thyroid hormones. These hormones are responsible for growth, development, metabolism (the rate at which all chemical processes in the body take place) and many other functions throughout your body.

T3 specifically helps with the thermal regulation of the body and is essential for growth, development, and general homeostasis (stable state).

The thyroid gland produces T4 and then converts it into T3; this conversion process can be inhibited by inflammation. When your body is inflamed (for example, due to injury or illness), your thyroid may not produce enough T3. 

When your thyroid is not working optimally, this can result in an overactive thyroid gland (hyperthyroidism) or an underactive thyroid gland (hypothyroidism).

Thyroid hormones are responsible for many functions throughout the body, including regulating metabolism. It is not rare to see low levels of thyroid and rapid weight gain in the same individual.  Let's discuss common types of thyroid disorders. 


Hyperthyroidism is when you have an overactive thyroid gland that generates too much thyroid hormone. This results in symptoms such as:

  • Fast heart rate
  • Increased appetite
  • Excessive perspiration
  • Weight loss
  • Nervousness, irritability, and/or anxiety
  • Diarrhea
  • Sensitivity to heat
  • And more!


Hypothyroidism is when you have an underactive thyroid gland that does not generate enough thyroid hormone. This results in symptoms such as:

  • Fatigue and excessive sleepiness
  • Weight gain or inability to lose weight
  • Depression, mood swings, and/or irritability
  • Muscle pain and stiffness
  • Cold intolerance
  • Constipation and dry skin
  • And more!

Primary, Secondary, Tertiary, and Subclinical Hypothyroidism

There are different types of hypothyroidism. 

  • Primary Hypothyroidism. This is when the thyroid gland itself does not maintain adequate levels of T3 or T4. This can be caused by a number of things, but the most common cause in the U.S. is Hashimoto's Disease. In primary hypothyroidism the problem is with the thyroid itself.

  • Secondary Hypothyroidism. This is when the pituitary fails to produce enough Thyroid-Stimulating Hormone (TSH) in response to low levels of thyroid hormone in the blood. This can be caused by pituitary disease, hypothalamic disease, medications that reduce TSH (such as amiodarone or lithium), autoimmune destruction of the pituitary, and more. In secondary hypothyroidism, the issue is not with the thyroid but the pituitary, which monitors the thyroid.

  • Tertiary Hypothyroidism. This is when the hypothalamus fails to produce enough thyrothropin-releasing hormone (TRH).  TRH is needed to stimulate the pituitary to produce enough TSH. TSH is necessary to stimulate the thyroid gland. Research shows that this can be caused by hypothalamic disease, medications that reduce TRH (such as lithium), autoimmune destruction of the hypothalamus, and more.

  • Subclinical Hypothyroidism. This is an early, mild form of hypothyroidism. Usually, your thyroid is functioning properly but your TSH levels are slightly elevated. This form of hypothyroidism is most common in women, the elderly, and those with other autoimmune diseases.

There's more to come. See you on Thursday!

To your longevity,

Anil Bajnath MD
CEO/Founder, Institute for Human Optimization
Chief Medical Officer, Longevity Insider HQ

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