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Hypothyroidism is a health condition that is caused due to an underactive thyroid gland, which results in decreased production levels of the thyroid hormones. The thyroid gland is located in the cat's neck below the larynx and is a small butterfly-shaped organ. The thyroid gland is responsible for the production of two hormones in your cat, T3 (triiodothyronine) and T4 (thyroxine), which affect the metabolic rate of the body.

The thyroxine hormone T4 is very important to the bodily function of a cat. It is required for food metabolism, growth, heart function, cognitive function, maintenance of muscle and bone and immune function.

Surgical removal or destruction (as a result of the treatment for hyperthyroidism, use of radioiodine or antithyroid drugs) of the thyroid gland is the most common cause of cat hypothyroidism symptoms. Hypothyroidism in cats is very rare and when it does occur it is due to the thyroid gland itself.


  • Obesity without an appetite increase
  • Coat and skin changes are most common - excessive shedding, dry skin, infections
  • Lethargy - lack of interest in walks, exercise, and play
  • Intolerance to cold - looking to lie in a warm place
  • Depression and aggressive behavior
  • Anxiety
  • Seizures
  • Infections
  • Slow heart rate

Cat hypothyroidism symptoms and signs can vary in pets as the deficiency of the hormones affects the function of the body and all the organs. Cats that develop the condition at a young age, or ones that are born with it, may often be unusually small and may also show signs of mental dullness, low heart rate, lethargy, and even constipation.

How to Support Cats with Hypothyroidism

Cats with hypothyroidism need treatment for life. If you suspect that your cat has hypothyroidism symptoms, a vet visit is highly recommended. Your vet will be able to conduct the required blood work to determine and diagnose the disease. Common allopathic cat hypothyroidism treatment uses the drug thyroxine, a synthetic hormone. It should be noted that over time the thyroid gland will completely stop producing the hormone as the gland’s feedback system will indicate that it does not need to produce the hormone anymore due to the use of the synthetic hormone.

The holistic approach is to support the body and help it produce the thyroid hormone using herbs and diet. Dietary supplements, such as Thyro UP, can be used to support the body if your pet is diagnosed with hypothyroidism. It can also be used as a preventative supplement for those cats that may be predisposed to the condition.

Additional Support

Never attempt to diagnose your cat on our own. Your vet will be able to perform the required test and make the necessary suggestions. Vegetables such as broccoli and cabbage should not be fed in large quantities to cats with hypothyroidism symptoms, as it can reduce the production of thyroid hormone.

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