Low thyroid function or hypothyroid affects approximately 15 million in the US. Hypothyroid is the most common thyroid disorder. It is five times more common in women compared to men in the US according to the Academy of Family Physicians in 2004.The generic form of Synthroid, Levothyroxine, is the fourth most prescribed medication in the US and 70.5 million prescriptions were done in 2010 alone!

The thyroid gland is the most common site for autoimmune attacks and is usually the first organ/gland to demonstrate autoimmune changes. Hasimoto’s is the most common autoimmune disorder in the US. It is estimated that 70 – 90% of all hypothyroid problems in the US are due to Hashimoto’s thyroiditis!

Many of these hypothyroid disorders are not diagnosed in the early stages and are mistaken for other problems. “Thyroid symptoms are so common and are often mistaken for signs of aging, menopause, depression or stress” according to Gay Canaris M.D. assistant professor of internal medicine, University of Nebraska Medical Center. Often women are not diagnosed until age 35-50 when symptoms often times significantly worsen. The progressive destruction and dysfunction of the thyroid worsens with age. It is estimated that 20% of American women by age 60 have a hypothyroid/ Hashimoto’s problem.


This is essentially a condition in which the body’s immune system attacks and destroys its own tissues, glands or organs. Hashimoto’s is the most common of this group of diseases. Some others are: Lupus, Addisons, multiple sclerosis, scleroderma, Sjogren’s, rheumatoid arthritis, interstitial cystitis, fibromyalgia, endometriosis, celiac, type 1 diabetes, pernicious anemia, vitiligo and many others.

The combination of genetics and an imbalanced, out of control immune system is the basic mechanism of these types of diseases. There may be several things that trigger these immune imbalances such as: hormone imbalances, poor diet, drugs, stress, environmental toxins, infections or subclinical infections.


Hypothyroidism or low thyroid can have widespread effects on the human body. The reason for this is that every cell, tissue, gland and organ have receptor sites for thyroid hormones. Thyroid hormones affect a very basic part of physiology which is basal metabolic rate. The lack of proper thyroid hormones will cause all the cells in the body to decline in function. The thyroid is analogous to a central gear in a complex web of body metabolism The thyroid is also very sensitive to other imbalances in the body. Keep in mind that most often many symptoms of hypothyroidism are initially vague and develop slowly over time. One of the earlier signs of low thyroid is elevated cholesterol. The following are some of the major signs and symptoms of being hypothyroid :

  1. Fatigue, weakness
  2. Unexplained weight gain
  3. Cold sensitivity, cold hands and feet
  4. Depression, anxiety, and other cognitive problems
  5. Constipation, bloating and gall bladder problems
  6. Dry skin, brittle nails, thinning hair, acne, puffy face,
  7. Muscle achiness, muscle cramps, joint pain and swelling
  8. Heavy menstrual flow, infertility in women
  9. Headaches
  10. Slowed or accelerated heart rate 11. Hoarse voice


A little understanding of the thyroid gland and thyroid hormones will give you greater appreciation of the complexities of the body. The thyroid is a butterfly shaped gland located below a prominence of the larynx commonly known as Adam’s apple. The gland surrounds the thyroid cartilage in the neck. The gland weighs about one ounce. Sometimes enlargements of this gland occur and are referred to as goiters.

There is an area of the brain referred to as the hypothalamus. The hypothalamus releases a hormone called thyroid releasing hormone (TRH). TRH then stimulates another gland at the base of the brain called the pituitary gland. The pituitary then releases a hormone called thyroid stimulating hormone (TSH) which then causes the thyroid to manufacture and release its two main hormones. The thyroid produces thyroxine or T4 and triiodothyronine or T3. T3 is the active form of T4 and T4 is metabolic inactive. What is interesting the thyroid secretes about 94% inactive T4 and 7% active T3. It is almost as if the thyroid produces an abundance of “backup amounts” of thyroid hormone. Most of the T4 is converted to T3 in the liver. The liver converts about 40% of the T4 to T3. There is an additional 20% of T3 converted to free T3 at the level of the small intestine. Therefore, it is important to make sure that there is proper liver and intestinal function to allow these conversions to take place adequately. As the levels of T4 and T3 become elevated in the blood. These hormones have an inhibitory effect on both the hypothalamus and pituitary gland. Essentially slowing down further thyroid gland hormone production. In biological science, this is referred to as a negative-feedback loop.

About 99% of the T4 and T3 released by the thyroid into the blood is bound (attached) to several proteins. These bound hormones are totally inactive. It is believed that the “unbinding” occurs mostly at the liver and kidneys. The hormones that are unbound are metabolically active and are called free T4 and freeT3. Therefore, a blood test measuring freeT4 and freeT3 is essential to get a better picture of the active hormone levels available to stimulate cell activity.

Another interesting factor affecting active levels of T4 and T3 are levels of testosterone and estrogen. Elevated levels of estrogen will cause increased levels of bound T4 and T3. Therefore, less available free T4 and freeT3. Testosterone will do the opposite. Therefore, birth control pills, hormone replacement for menopause and other environmental toxins that mimic estrogen (environmental endocrine disruptors) potentially can create thyroid imbalances.

Many different stressors can cause the adrenals to produce elevated levels of a stress hormone called cortisol. Cortisol inhibits the liver’s conversion of T4 to T3. It also converts T3 to an unusable form called reverse T3. Therefore, adrenal imbalances can lead to improper thyroid stimulation.

The hypothalamus can be inhibited if there is improper production of neurotransmitters in the brain. Namely, dopamine and serotonin. Improper levels affect TRH produced by the hypothalamus and TSH by the pituitary. Again stress, blood sugar imbalances, allergies and other causes of systemic inflammation can cause shifts of these neurotransmitters. Low thyroid also causes changes in these “brain chemicals”.

Lastly, the cells themselves may not respond properly even though there are normal levels of freeT4 and T3. The receptors for the thyroid hormones become less sensitive or the cell’s internal or nuclear response is impaired. This can due to other hormonal imbalances, toxins, infection, oxidative stress and other factors.


This immune attack on the thyroid is the number one cause of hyperthyroidism here in the US. Worldwide the number one cause is iodine deficiency. In order to determine if you have Hashimoto’s a blood test measuring antibodies to a thyroid enzyme called thyroid peroxidase or TPO Ab is necessary. What also should be evaluated is a complete immune cell and cytokine panel to determine the status of the immune system. As a reminder, cytokines are compounds released mostly by white blood cells called lymphocytes. Cytokines often determine levels of inflammation caused by the immune system.

There are several causes leading to these autoimmune imbalances and attacks such as: elevation of estrogen, insulin surges, PCOS, environmental toxins, vitamin D deficiencies, stress, environmental toxins, food sensitivities especially to gluten, other allergies, subclinical infections and genetics. Those with Hashimoto’s need to avoid extra iodine as this will worsen the condition.


Whether you have just a low thyroid condition or Hashimoto’s (more likely here in US) most physicians will treat the condition the same. No concern as far as the mechanism of hypothyroidism is given, simply supply the patient with thyroid hormone replacement often synthetic T4 levothyroxine, Synthroid or similarly related. However, if there has been extensive damage to the thyroid it may be necessary to utilize hormone replacement. So, it is better to have a person evaluated with a complete thyroid panel, including TPO Ab, TBG Ab, freeT4, freeT3 and not just TSH especially with continued symptoms of fatigue or if there is a genetic tendency for thyroid problems in the family. Addressing the immune issues earlier will help to prevent further damage to the thyroid tissue and imbalances to the rest of the body.

Synthroid is not bio-identical to human thyroxine T4. They are structurally different, but similar enough to impact metabolism. Synthroid and other similar medications often contain cornstarch which can elicit an immune reaction!