Hypothyroidism in Dogs

What is Hypothyroidism?

This is a condition most commonly caused by an immune-mediated attack of the thyroid gland, reduced production of the thyroid hormone ‘thyroxine.’ This hormone controls the body metabolism and reduced production results in a slower metabolic rate.

What are the symptoms?

The classic signs of hypothyroidism may include one or all of the following:

  • Weight gain

  • Slow heart rate

  • Lack of energy

  • Skin problems

  • Hair loss

How is the disease diagnosed?

A blood sample is taken to assess thryoid hormone levels. However, this can be sometimes be low due to other underlying problems. Therefore the levels of the hormone that stimulate thyroxine production also needs to be tested, this hormone is called ‘thyroid stimulating hormone (TSH).’

Unfortunately approximately 35% of dogs will have a false negative result and further tests may need to be performed.


Hypothyroidism is generally quite easy to treat. Your pet will be treated with replacement hormone therapy in the form of a tablet. Regular monitoring of thyroid levels and clinical symptoms are necessary to ensure adequate control.

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