The thyroid is a small gland located at the base of the neck, in the front. The thyroid gland controls many body functions through the production of thyroid hormones: thyroxine (T4) and triiodothyronine (T3) (Video). The production of thyroid hormones is, in turn, controlled by the "thyroid stimulating hormone (TSH) secreted by the pituitary gland, a gland located inside the skull. The thyroid hormones regulate important functions of the organism, including breathing, heartbeat. heart rate, body temperature, central nervous system development, and body growth (Video).

If the thyroid does not produce enough thyroid hormones, a condition called hypothyroidism occurs. In its early stages, hypothyroidism rarely causes ailments but, over time, if left untreated, it can cause a variety of health problems, such as obesity, joint pain, infertility and heart disease. Both men and women can suffer from it. if it is more common among women, especially over 60 years of age.

If hypothyroidism occurs in the fetus, usually from thyroid developmental defects, it causes severe mental and growth retardation.


In adults, early stage hypothyroidism rarely causes ailments (symptoms) but, if left untreated, it can cause a variety of health problems over time.
If it occurs in the fetus and / or child in the first years of life, it can cause severe retardation of the growth and development of the central nervous system.

In adults, the symptoms caused by hypothyroidism tend to develop slowly and, therefore, it is more difficult to recognize them. They include:

  • fatigue
  • increased sensitivity to cold
  • constipation
  • dry skin
  • weight gain
  • puffy face
  • hoarseness (lowering of the voice)
  • weakness and muscle aches
  • stiffness, swelling or pain in the joints
  • high blood cholesterol levels
  • irregular menstrual cycle
  • hair loss
  • slow heart rate
  • depression
  • memory changes


The main causes of hypothyroidism can be:

  • iodine deficiency: Iodine deficiency is the leading cause of hypothyroidism worldwide, especially in underdeveloped countries. The thyroid needs iodine to form thyroid hormones. In nature the main source of iodine is represented by food, however, often the iodine introduced with food is insufficient to meet the daily requirement. The World Health Organization (WHO), therefore, invited the populations to consume salt enriched with iodine to compensate for the deficiency
  • thyroiditis (in particular chronic autoimmune or Hashimoto's thyroiditis): they constitute one of the most frequent causes of hypothyroidism. They are autoimmune diseases, that is, caused by an error in the immune system that damages thyroid cells, or by a viral infection. This last form can be temporary
  • removal of the thyroid gland: may be needed due to nodules, thyroid tumors or hyperthyroidism, resistant to medical therapy
  • radioactive treatment: used for hyperthyroidism, goiter or thyroid tumors
  • damage to the pituitary gland (gland that controls all other glands including the thyroid): for tumors or for surgery or radiotherapy. If the pituitary is damaged, the thyroid gland does not produce thyroid hormone
  • taking medications: such as lithium, amiodarone and interferon
  • congenital hypothyroidism (IC): it consists of a hypothyroidism present at birth (affects 1 in 3000 - 4000 newborns), caused by a lack of the thyroid gland, or by a small thyroid or by a thyroid located in an abnormal site (ectopic thyroid). Lack of thyroid hormone from birth can lead to severe damage to all organs and systems. Today, an adequate and timely diagnosis is possible through newborn screening

Certain factors can increase the risk of developing thyroid malfunction; they include:

  • sex / gender: The female population is more likely than men to develop thyroid dysfunction
  • age: over 50 years old
  • thyroid problems in the past: having thyroid problems during pregnancy, or family members who have suffered from hypothyroidism, increases the risk of developing it
  • smoke, smokers and former smokers have a higher risk of developing autoimmune thyroid dysfunction


When you feel the symptoms described for thyroid disorders it is good to contact your doctor who, after a visit, will evaluate the prescription of some tests.
In fact, to ascertain hypothyroidism, simple blood tests are sufficient in which the levels of thyroid hormones are assessed.

Normally, blood levels of thyroid stimulating hormone (TSH) and thyroxine (T4) are measured; Triiodothyronine (T3) is also sometimes measured. Low T4 levels and high TSH levels are indicative of hypothyroidism.

Once hypothyroidism has been diagnosed, the doctor may also prescribe an ultrasound scan to examine the structure and size of the thyroid, highlighting the possible presence of nodules or goiter.


The therapy of hypothyroidism is usually simple, safe and effective and involves taking by mouth, every day, the thyroid hormone T4 (levothyroxine) in tablets in order to restore adequate levels of the hormone, removing the signs and the disorders (symptoms) of hypothyroidism.

Levothyroxine is usually marketed in the form of tablets (in Italy prescribed in range A, therefore paid for by the National Health Service) to be taken by mouth, on a completely empty stomach. This is why it is recommended to take the drug in the morning before having breakfast. After taking the tablet it is essential to wait at least 30 minutes before eating, to prevent food from interfering with the absorption of the hormone.

Side effects of levothyroxine usually occur when too much dosage has been taken and can be:

  • irregular heartbeat
  • muscle cramps
  • He retched
  • diarrhea
  • weight loss
  • sleep problems
  • headache
  • sweating

Once the right dosage of the drug is reached, the side effects disappear.

The drug is taken for life.


Higher Institute of Health (ISS). National Congenital Hypothyroid Registry (RNIC)

Higher Institute of Health (ISS). National Observatory for the Monitoring of Iodoprophylaxis in Italy (OSNAMI)

In-depth link

Ministry of Health. Iodine and health

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