Thyroid Malfunction - A Reason for Weight Gain

Annette Nay, Ph.D.

Copyright © 2003

The thyroid is responsible for how well your metabolism works.  The higher the metabolism the more fat is burned which results in a higher weight loss.  If the thyroid is sluggish or not working at all, the body stores fat and you become fatter, even if you are dieting and exercising.

There are times in one’s life where the thyroid tends to slow down production of the chemicals the metabolism needs to do its job.  This slows down the metabolism making it harder to loose weight.  Aging and menopause are the usual causes.  Multiple Sclerosis sufferers also tend to have problems sooner or later with their thyroid causing excessive weight gain.  

Signs of a sluggish or malfunction thyroid (hypothyroidism)

If you have difficulty loosing weight accompanied by low energy plus any of the following:

  • Flaky dry skin

  • Headaches

  • Depression or mood swings

  • Constipation

  • Insomnia

  • Hair loss

  • High cholesterol

  • Poor concentration or memory

  • Difficulty staying warm

See:  Untreated Allergies causes Many Illness, Autoimmune Diseases, Hypothyroidism, Cancer and Ultimately, Death



Richland College


Student Projects for Biol. 2402

Anatomy & Physiology Project Members:

Daniel Lewis, Heather Ewing

Sunnie Erwin, Kristi Pruitt


The thyroid gland is the largest pure endocrine gland in the body, and is located on the trachea just inferior to the larynx (Adams apple). The major role of the thyroid gland is the production of TH or thyroid hormone, which is the hormone that controls the metabolic rate of our body and is what controls the body's temperature. There are two active iodine-containing hormones, thyroxine, (T4) and triiodothyromine (T3). Hypothyroidism refers to the condition in which the production of thyroid hormone decreases below the normal level.

Hypothyroidism is a chronic endocrine mediated disease process. There is a "slowing" of bodily functions as a result of thyroid hormone deficiency. This deficiency can cause Myxedema. Myxedema coma is a rare life threatening condition in the progression of hypothyroidism. See Hypothyroidism with Myxedema

Hypothyroidism is the most common functional abnormality, and the most common cause of hypothyroidism is Hashimotos thyroiditis. There are other causes of hypothyroidism such as surgical removal of the thyroid gland, radioactive iodine treatment, extreme radiation, and a deficiency in dietary iodine consumption (this is rare in the U.S.) which will result in a simple goiter. More on the world of

In comparison to severe hypothyroidism, mild thyroid failure may cause no symptoms at all and those with it may feel entirely well. However, studies show that many people with mild hypothyroidism eventually develop more severe thyroid failure in later years.

Hypothyroidism can occur spontaneously, be inherited, or develop after hyperthyroid treatment. Secondary hypothyroidism, on the other hand, occurs when the pituitary gland is damaged and fails. This type of failure is rare and is usually caused by a tumor. When secondary hypothyroidism does occur, the pituitary gland can no longer produce TSH, which stimulates the thyroid gland to produce TH. Patients with chronic hypothyroidism are highly vulnerable to the other associated autoimmune diseases. With that in mind, other diseases also affect hypothyroidism. Learn about the Thyroid here.


Hypothyroidism has many levels, ranging from borderline to the more severe, Hashimoto's disease. The severity of the disorder is characterized by the amount of decrease in the hormones secreted by the thyroid. The symptoms that occur with the disease vary depending on the length of time the body has been deprived of the proper amount of hormone.

Mild cases of hypothyroidism usually have few symptoms and patients feel fine. However, after being treated report that they do have an improvement in the way that they feel. Because symptoms are not present, or are usually so vague, treating or diagnosing mild cases are often very difficult. Testing levels of TSH (thyroid - stimulating hormone) in the blood stream along with the reduction in the amount of thyroid hormone levels, is the only definite way to diagnose mild hypothyroidism.

More severe cases of hypothyroidism are easier to diagnose. Symptoms include fatigue and muscle swelling or cramps (mainly in the arms and legs), tingling in the fingers, loss of equilibrium, weight gain or increased difficulty losing weight, dry sometimes itchy skin, cold intolerance, coarseness or loss of hair, husky voice, constipation, memory and mental impairment, decreased concentration, goiter, depression, irregular or heavy menstruation, infertility or miscarriages, drooping swollen eyes, and a slowed heart rate. The two most common symptoms are fatigue and cold intolerance. Not all of these symptoms may occur, usually just a few, but with the severity of the disease the more will be present.

Symptoms usually disappear after treatment has taken place. Since hypothyroidism is a deficiency in thyroid hormones, treatment includes the replacement of the hormones the thyroid should secrete. Once diagnosed, the treatment is easy, the most difficult part is trying to determine if the deficiency is present, and to what degree. Many of these symptoms occur naturally with age. The presence of two or three symptoms should be of no concern. However, if several of the symptoms are present, you may want to have your hormone levels checked.

The key signs to secondary hypothyroidism are a history of absence of menstruation of three or more periods in a row (known as Amenorrhea). In secondary hypothyroidism, symptoms include low blood pressure, hypoglycemia (often found because of a concomitant adrenal insufficiency or growth hormone deficiency), a reduction in breast size, skin depigmentation, and dry skin and hair.


Primary hypothyroidism in some women cause them to have an abnormally long (longer than seven days) or heavy menstrual flow, frequently accompanied by the passing of large blood clots.

People with Hashimoto's thyroiditis complain of painless enlargement of the thyroid gland. The doctor might notice a non-tender goiter; which may appear smooth or nodular, firm, and more rubbery in consistency than the normal thyroid. Twenty percent of patients have hypothyroidism when first seen.

Tests show that circulating TSH levels in the blood are low with people who have secondary hypothyroidism. Where as in people with primary hypothyroidism, the TSH levels are very high. To diagnose primary hypothyroidism the serum TSH is the most simple and sensitive test.

In Hashimoto's Thyroiditis, there are normal T4 levels and a high level of antithyroid antibodies at an early age. The gland continues to absorb iodine which leads to malfunction of the thyroid. Later the patient develops hypothyroidism with a decrease in T4 and RAI uptake. Replacement of thyroid hormone to correct and prevent hypothyroidism must continue throughout life. If such a deficiency remains undiagnosed, this will ultimately result in death.

Evaluation will include history and physical examination. Blood test (i.e. thyroid profile, blood counts and blood chemistry will be performed. The thyroid profile will show a low hormone level consistent with this diagnosis. Special serologic blood test such as thyroglobulin antibodies may also be performed. A nuclear thyroid scan may be indicated in some cases.

Treatment includes supplementation with a synthetic thyroid hormone (Synthroid). Close medical follow-up is necessary to determine the proper dose necessary to maintain normal metabolic function. Internist or Endocrinologist are the experts in the management of this disorder.

Annette Nay, Ph.D.


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