Dog Tips

Hypothyroidism in Dogs

The thyroid glands, which are situated on either side of the neck near the throat, are responsible for producing thyroid hormones. In dogs with hypothyroidism, a common endocrine disorder, the thyroids produce fewer thyroid hormones than normal. A dog's metabolism is significantly influenced by these hormones, and slows down when the glands are not generating enough hormones. Two primary causes of hypothyroidism are Thyroiditis and Atrophy.1

What Causes Hypothyroidism in Dogs?

Idiopathic thyroid gland atrophy or lymphocytic thyroiditis accounts for over 90% of hypothyroidism cases in dogs.2 Although little is known about both disorders, both cause thyroid impairment in dogs.

Thyroiditis: This is when the immune system of the dog attacks the thyroid glands. The condition frequently has a hereditary origin and can require lifelong treatment to manage.

Atrophy: Fat and connective tissue take the place of the normal thyroid tissue. This could potentially be the last phase of thyroiditis.

Cancer: While uncommon, cancer can cause hypothyroidism in dogs. The majority of hypothyroidism patients either have degeneration or inflammation of the thyroid gland, both which can be treated with medicine.

What Breeds are Prone to Hypothyroidism?

When hypothyroidism does occur, it usually affects dogs between the ages of three and five, and medium-to-large breeds are more likely to be afflicted.2 Breeds that can be prone to this condition include; Irish Setters, Miniature Schnauzers, Doberman Pinschers, Dachshunds, Golden Retrievers, and Cocker Spaniels.

What are the signs of hypothyroidism in dogs?

Since hypothyroidism slows down your pet's metabolism, it can affect nearly every organ in your dog's body. You may observe one or more of the following signs if your dog has hypothyroidism.

  • Weight gain without an increase in food or appetite

  • Fatigue and lack of motivation to play or run

  • Slow heart-rate

  • Cold intolerance

  • Increased pigmentation of the skin

  • Thinning of coat

  • Dry and dull hair with excessive shedding

  • High blood cholesterol

Some dogs can exhibit additional abnormalities, such as - thickening of facial skin, lack of coordination, dry eye, infertility, and miscarriage in female dogs.

How is Hypothyroidism Diagnosed in Dogs?

A blood test can identify hypothyroidism. Your veterinarian will take a blood test to analyze or send to a lab for results. A screening test known as a total thyroxine level (also known as a total T4 or TT4) is most frequently used to diagnose this condition. Lab tests may reveal abnormalities such as high cholesterol, abnormal kidney function, and anemia. In some cases diagnosis of hypothyroidism may be difficult to confirm and require repeated testing.3

How is Hypothyroidism Treated in Dogs?

Hypothyroidism can be managed but not cured. One synthetic thyroid hormone that your veterinarian may prescribe is Levothyroxine. Although it is typically given twice daily, some dogs can benefit from just one dose a day.2 Your dog will need to stay on this medication for the rest of their life.

Your dog's required dosage will be based on their weight. To confirm that the thyroid hormone levels are returning to normal, a blood sample will need to be taken one month into the therapy regimen. Because hormone levels can change, the blood sample is often drawn either right before or four to six hours after the medicine is administered. It's important to maintain close contact with your veterinarian to help ensure your dog isn't receiving an excessive or insufficient dosage.

Since the thyroid and a dog's metabolism impact almost every organ in the body, untreated hypothyroidism can reduce your dog's lifespan. Untreated hypothyroidism in dogs causes neuromuscular symptoms, slowed heart rate, elevated cholesterol, and weaken the immune system.1 The neuromuscular symptoms can include head tilts, dizziness, and even seizures.

If your dog has an underlying heart condition, they should be closely monitored by their veterinarians after first starting thyroid hormone replacement therapy. The dose of their heart medication may need to be adjusted depending on the dog’s response to treatment.

Are There Any Diet Recommendations for Dogs With Hypothyroidism?

A balanced diet which is rich in probiotics, antioxidants, vitamins, minerals, amino acids, lipids, and carbs is essential for dogs suffering from hypothyroidism. Talk to your vet and ask them to recommend a dog food that will meet your dog's nutritional needs.

Ask your veterinarian to suggest a holistic veterinarian or pet nutritionist in your area if you want more guidance creating the right diet for your dog. These diets are designed specifically to provide all the nutrients your pet needs but with less fat. Learn more about holistic pet care.

What is the Prognosis for Dogs With Hypothyroidism?

With an accurate diagnosis, as well as appropriate treatment and monitoring, hypothyroidism carries a good prognosis (overall success rate).3 Many of the odd symptoms your dog experienced can improve in just a few weeks, but it can take several months for their skin and coat to improve and for hair to regrow.

Are There Any Holistic Treatments for Hypothyroidism in Dogs?

When considering treatment options for hypothyroidism, medication might be your first choice. However, there are a variety of holistic or natural alternatives that can also assist in enhancing your dog's quality of life, including:

Plants and herbs such as ashwagandha, turmeric, mushrooms, and kelp can help improve immune function. That being said, do not start treating your dog with herbs at home, speak to your vet and get their go ahead before introducing any new foods to your pet's diet.

Homemade Diet for Hypothyroidism

Depending on your pet's needs your veterinarian might approve them to have a homemade holistic diet. Additionally, if you prefer to not prepare the food yourself, there are plenty of prescription dog foods that contain all the nutrients your dog needs to stay healthy as well as a blend of vitamins and minerals to help control their hypothyroidism. Just remember, before introducing new food to your dog's diet, make sure to consult your veterinarian.


Since the thyroid gland is an important gland hypothyroidism must be properly managed with the help of a vet. It is a treatable condition but can cause unexpected weight gain, skin conditions, and behavioral changes. Pet parents can typically see improvement in their dog's activity level after the first few weeks of treatment but it can take a few months to notice improvements with a pets skin and hair.

  1. "Hypothyroidism in Dogs," PetMD,, Feb. 3, 2022.

  2. "Hypothyroidism in Dogs," Pawlicy Advisor,, accessed Jan. 26, 2024.

  3. "Hypothyroidism in Dogs," Carolina Veterinary Specialists,, accessed Jan. 26, 2024.

The information presented in this article is for educational and informational purposes only and does not constitute or substitute for the advice of your veterinarian.

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