Understanding Hypoactive Thyroid Causes, Symptoms and Treatments


When the thyroid gland is not responding to the pituitary gland’s release of thyroid stimulating hormone, the result is a hypoactive thyroid, or hypothyroidism, and insufficient levels of thyroid hormone in the blood.  This condition affects more women than men, and requires life long treatment to replace the hormones not being produced by the thyroid.

Thyroid hormones

The hormones secreted by the thyroid are:

Thyroxine (T4), which contains four atoms of iodine.
Triiodothyronine (T3), has three atoms of iodine attached

Thyroxine is turned into Triiodothyronine by the liver, and it is these hormone levels that determine the type of thyroid disease that is present. These hormones work to regulate the rate at which your body burns energy.  They affect weight and sleep patterns, menstrual cycle changes in women and sexual dysfunction (ED) in men.

Another hormone involved in this process is thyroid stimulating hormone (TSH), manufactured by the pituitary gland.  When thyroid hormone levels in the blood are low, the pituitary gland releases TSH, which stimulates the thyroid to produce and secrete more hormone.


Subclinical hypothyroidism is the term that describes the initial symptoms of hypothyroidism that can be overlooked and mimic other conditions.  Symptoms include:

Intolerance to cold
Dry and/or pale skin
Hair loss and brittle nails
sore muscles, slow movements and weakness
Hoarse voice
a change in facial expression
Memory deficits and difficulty in concentrating
Increased weight
fertility problems and increased risk of miscarriage
heavy, irregular or prolonged menstrual periods
Bradycardia (slow heart rate)

Goiter is a swelling in one or both lobes that site on either side of the thyroid gland, that appears as an enlargement on the lower aspect of the neck.


Hypothyroidism is more common in older people.
Women are more likely to be affected than men.
Autoimmune conditions such as diabetes, vitiligo, and Addison’s disease.
Certain medications, such as lithium carbonate (psychotropic med) and amiodarone (for the heart)
Inefficient amount of iodine
Autoimmune Hashimoto’s thyroiditis
Problems with hypothalamus or pituitary gland

Hypothyroidism is diagnosed by testing the blood TSH levels and thyroid hormone levels in the blood. A diagnosis of autoimmune hypothyroidism is usually determined by the presence of certain antibodies in the blood, which show as a problem with autoimmunity.


Treatment for Hypothyroidism involves replacing the thyroid hormones that are absent.  This is easily accomplished by taking oral levothyroxine.  The dosage will need to be adjusted by your physician to get the correct dosage for you. Regular blood testing will be required to check hormone levels.  Medication will then be adjusted accordingly.  Medication and treatment for underactive hypothyroid will continue for the rest of the patient’s life.  Once the correct dose of thyroxine replacement has been determined, yearly blood tests will be needed to ensure appropriate hormone levels are maintained.

Fetal thyroid development occurs after the 12th week of pregnancy.  Until then the fetus depends on the mother’s thyroid hormone levels for nervous system development.  The mother can feel safe in taking her thyroid supplements.  She needs it for her health, as well as for the health of the developing fetus.

If you are hypothyroid and plan to have children sometime in the future, let your doctor know of your plans so that your health can be in the most optimal condition as possible.