An underactive thyroid, also known as hypothyroidism, is a condition in which the thyroid gland does not produce enough of certain hormones. While it may be a problem directly with the thyroid, it could be a secondary reaction of damage done to the pituitary gland. Symptoms are often unclear in the early stages, but accurate thyroid function tests are fairly accurate. Once proper diagnosis has been established, treatment can begin. Certain people are more susceptible to developing thyroid disorders. While it is not overly common, women tend to experience symptoms after the age of 50. They often confuse the symptoms as a sign of growing older. Congenital hypothyroidism is a thyroid condition that affects infants from birth. Normally, teens and young adults do not develop thyroid disorders such as an underactive thyroid, but it is not unheard of.

 
The signs of this hormone disease vary widely. They are commonly attributed to aging, but should be mentioned to a physician to be safe. The first sign of an underactive thyroid is often weight gain. While it may be simply a slowing metabolism, it could be more serious. The second most apparent symptom is feeling tired far more frequently or more easily than normal. Hair loss and pale, dry skin are often quick to follow.
There are many other symptoms that are also associated with an hypothyroidism. These may include increased sensitivity to the cold, constipation, a hoarse voice, and heavier menstrual periods. Muscle aches, stiff joints, and a hoarse voice should also not be ignored. Because an underactive thyroid affects the hormones in the body, it is also possible that it may cause depression or other mental instabilities.

If left untreated, hypothyroidism can contribute to heart disease in the long run. An underactive thyroid can result in an elevated blood cholesterol level and high blood pressure. Blood tests can help to determine if there is a thyroid problem and if there is a danger of developing heart problems, and action can be taken to reverse the damage and prevent further complications.

Hypothyroidism is also classified as an autoimmune disease. When the thyroid fails to produce the necessary antibodies that fight off infection and potential illness, the immune system is compromised. A lowered immune system is more dangerous than the direct symptoms of an underactive thyroid, especially for those who are elderly and infants.

While a variety of hormones may be low in someone with an underactive thyroid, the most common are thyroxine and triionothyronine. The lack of these hormones will cause the symptoms, such as fatigue and a lowered immune system, to be elevated. A synthetic version of the hormone, levothyroxine can help to alleviate the symptoms and improve the thyroid functions, and scientists are in the process of creating synthetic triionothyronine.
An underactive thyroid can become a burden on daily life. The feelings of fatigue and even depression can prevent people from interacting in their usual activities. Discussing the problem with a doctor early on will make it easier to receive treatment and help resolve problems.