The Difference between Hyperthyroidism and Hypothyroidism


The thyroid is responsible for producing the three hormones thyroxine (T4), triiodothyronine (T3) and calcitonin, the former two being responsible for the conditions hyperthyroidism and hypothyroidism. In layman’s terms, hyper means too much and hypo means too little (hypothermia is freezing, hyperthermia is overheating). So these two conditions are the result of the thyroid producing too much or too little of these hormones.

This can be a result of diet, disease (often autoimmune disease), a result of other treatments, and birth defects. Some of the causes mean treatment is life long, while others require only weeks or months of treatment.


Symptoms include:

  • Tiredness
  • Sensitivity to cold
  • Weight gain
  • Constipation
  • Depression
  • Slow movements and thoughts
  • Muscle aches and weakness
  • Muscle cramps
  • Dry and scaly skin
  • Brittle hair and nails
  • Loss of libido (sex drive)
  • Pain, numbness and a tingling sensation in the hands and fingers (carpal tunnel syndrome)
  • Irregular periods or heavy periods

The main cause of hypothyroidism is an autoimmune disease. In this case, it is called Hashimoto’s disease, and it runs in families.

It can also occur due to previous thyroid treatment, particularly from hyperthyroidism medication. Sometimes babies don’t fully develop their thyroid in the womb, which is uncommon and usually found during routine screening after birth.

The most common treatment for an underactive thyroid comes in the form of hormones that your thyroid produces. This is usually T4, but sometimes T3 which can be bought through third parties like T3 medication UK to support your recovery.

Changing your diet can also help recovery. Finding foods that have iodine, selenium and zinc in them will help your thyroid operate and protect it. These include sea-foods, eggs and legumes.


Symptoms include:

  • Nervousness, anxiety and irritability
  • Hyperactivity
  • Mood swings
  • Difficulty sleeping
  • Feeling tired all the time
  • Sensitivity to heat
  • Muscle weakness
  • Diarrhoea
  • Urinating more frequently
  • Persistent thirst
  • Itchiness
  • Loss of interest in sex

¾ of people experience hyperthyroidism due to the autoimmune disease ‘Graves’ disease’, it mostly affects middle-aged women and runs in families. In this instance, you would need to take medicine for the rest of your life, although symptoms can be relieved.

Excessive iodine can cause your thyroid to produce too many hormones. This is usually due to medication for other ailments and will return to normal when you stop using the medicine.

Another cause is thyroid nodules, non-cancerous, benign tumours that produce excess hormones.

A common treatment for hyperthyroidism a medicine called thionamides, which prevents your thyroid from producing excess hormones. This treatment usually takes 1-2 months and may include beta-blockers to reduce symptoms.

Another treatment is called radioactive iodine treatment, wherein a drink or capsule is consumed consisting of iodine and a low dose of radiation, which is absorbed by your thyroid and destroys its cells, resulting in fewer hormones being produced. Alternatively, surgery is occasionally available to remove cells in the same manner.

You can find more information on both conditions on the British Thyroid Association’s website.

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