Thyroid is a butterfly shaped gland located in front of the neck. It secretes two metabolically important hormones, called thyroxine and triiodothyronine that are vital for physical and mental growth.         Hypothyroidism occurs when the thyroid gland produces less than the normal amount of thyroid hormones. It is more common in females than males and prevalence increases with increasing age. About 1 in 50 women and about 1 in 500 men develop hypothyroidismat some time in their lives.  


  • Symptoms that commonly occur include tiredness, weight gain, constipation, aches, feeling cold, dry skin, lifeless hair, fluid retention, mental slowing, and depression.  
  • Less common symptoms include a hoarse voice, irregular or heavy menstrual periods in women, infertility, loss of sex drive, carpal tunnel syndrome (which causes pains and numbness in the hand), and memory loss or confusion in the elderly.  
  • In very young infants, it can result in irreversible mental and physical retardation, unless treatment is initiated within weeks after birth. 

If you have untreated hypothyroidism: 

You may have an increased risk of developing heart disease. This is because a low thyroxine level causes the blood lipids (cholesterol) to rise.  

If you are pregnant, you have an increased risk of developing some pregnancy complications. For example; pregnancy-induced hypertension, anaemia,  premature labour, low birth weight, stillbirth, and serious bleeding after the birth.  


  • Autoimmune thyroiditis - most common
  • Surgery or radioactive treatment to the thyroid gland

Other causes

  • Iodine deficiency
  • Congenital
  • Drugs - amiodaron, Lithium
  • Thyroiditis: Pituitary or Central 


A blood test can diagnose hypothyroidism.  

  • Thyroid-Stimulating Hormone (TSH). A raised level means the thyroid gland is underactive.  
  • Thyroxine (T4).  A low level of T4 confirms hypothyroidism.  
  • Thyroid autoantibodies – indicates a likelihood of autoimmune thyroiditis. 

Note: Some people have a raised TSH but have a normal T4 known as Mild or Subclinical Hypothyroidism. There is an increased risk of developing overt or clinical hypothyroidism in the future and needs follow up. 


The treatment is to take levothyroxine (thyroxine) tablets each day. This replaces the thyroxine which your thyroid gland is not making. Ideally, take the tablet on an empty stomach (60 mins before breakfast) for maximum benefit. This is because some foods rich in calcium, iron or soy products may interfere with the absorption of levothyroxine from the gut. 

How long is the treatment for?

For most people, treatment is for life. Occasionally, the disease process reverses.

Are there any side-effects from treatment?

Levothyroxine tablets replace the body's natural hormone, so side-effects are uncommon. If you take too much levothyroxine it can lead to symptoms of an over-active thyroid. For example, palpitations, tremor, irritability, and sweating, and increases the risk of developing osteoporosis. So follow your Doctor’s advice.