Although thyroid diseases in dogs are relatively common, dog hyperthyroidism – one disease of the thyroid – is pretty rare. Despite that, it pays to know the symptoms, causes, and steps you should take if your pet displays signs of it.


  1. Can Dogs Have Hyperthyroidism and Thyroid Diseases?
  2. Hyperthyroidism in Dogs Symptoms
  3. How to Spot Early Hyperthyroidism in Dogs
  4. What Happens When a Dog Has Hyperthyroidism?
  5. What Causes Dog Hyperthyroidism?
  6. High-Risk Dog Breeds for Thyroid Diseases
  7. How is Hyperthyroidism in Dogs Diagnosed?
  8. Canine Hyperthyroidism Treatments
  9. Natural Treatments for Hyperthyroidism in Dogs
  10. Emergency Fund
  11. FAQ

Can Dogs Have Hyperthyroidism and Thyroid Diseases?

Yes, dogs have a thyroid gland, so they can suffer from a range of conditions related to the thyroid system, including hyperthyroidism.

A dog’s thyroid gland can be found on the throat/neck. Shaped a little like a butterfly, the ‘wings’ sit on either side of the trachea, also known as the windpipe.

According to research, the gland is responsible for producing and releasing thyroid hormones, including T4, also known as thyroxine. These hormones aren’t responsible for a single process in the body but are instead responsible for a range of things, including metabolism.

Some experts refer to the endocrine system (thyroid) in dogs as the “thermostat” of the body.

Hyperthyroidism in Dogs Symptoms

One side effect of the thyroid gland producing too much of those thyroid hormones is that your dog will appear more ‘sped-up’ than usual. The following symptoms are all common with canine hyperthyroidism:

Certain causes of canine hyperthyroidism will bring different symptoms, too. Both benign and cancerous tumors on the thyroid gland can protrude from the skin, and they can sometimes be felt. Be careful when attempting to touch the mass; it can be painful for some dogs.

A mass on the thyroid gland, whether cancerous or benign, can also bring the following symptoms:

  • Difficulty swallowing food or water;
  • Heaving and coughing;
  • Unusual breathing or panting;
  • Changes to your dog’s cry, bark, or other vocal noises.

How to Spot Early Hyperthyroidism in Dogs

Some of the symptoms of this condition (and many others) are difficult to spot when you are out of the house and away from your pet for long periods of time, such as when you are at work. If you regularly leave your pet alone for prolonged periods, an interactive pet camera can offer a welcome lifeline.

As well as being able to rewind and playback footage of your pet, to see whether they are experiencing unusual symptoms when you’re not looking, you can check in on them from time-to-time. If something changes with your furry friend’s habits, behavior, or health, you’ll notice it immediately, and you’ll be able to do something about it.

Read more: 7 Critical Signs Your Pet Needs Immediate Veterinary Attention

What Happens When a Dog Has Hyperthyroidism?

Hyperthyroidism occurs when the thyroid gland produces too much T4 and other thyroid hormones. A delicate combination of those hormones is required for your dog to be fit and healthy, and when too much or too little of one or more is produced, your pet can become quite unwell.

Although thyroid disease is relatively common in dogs, hyperthyroidism is rare. It is more common for dogs to suffer from hypothyroidism. This occurs when the thyroid gland produces inadequate amounts of thyroid hormones.

What Causes Dog Hyperthyroidism?

There are several possible causes of canine hyperthyroidism. Some of the most common ones are:

Benign Thyroid Adenoma

This is a mass of tissue that grows in, on, or around the thyroid, disrupting hormone production and release. The mass is non-cancerous and benign.

This is the rarest cause of canine hyperthyroidism.

Hypothyroidism Overmedication

If your poor pooch has recently suffered from the opposite problem of hyperthyroidism, known as hypothyroidism, they would likely have been prescribed medication to counteract the problem. If too much of that medication is prescribed and administered, hypo can quickly turn into hyper — too little into too much.

Sensitivity to other medications can also, rarely, cause canine hyperthyroidism.

Consumption of Seaweed/Kelp

Whether in the form of literal human food or supplements that contain sea-based ingredients, links have been made between the consumption of seaweed and kelp-based products and hyperthyroidism in dogs.

Consumption of Raw Food Diets

Commercially manufacture red raw food diets are said to be one of the biggest culprits because of the risk of the meat being contaminated with thyroid hormones or thyroid tissue. If ingested, it can upset the delicate balance and cause hyperthyroidism.

Cancerous Thyroid Carcinoma/Adenocarcinoma

Cancer is the most common cause of hyperthyroidism in dogs. It is sometimes referred to as neoplasia.

It is more common for dogs to be diagnosed with cancer (and hyperthyroidism) aged ten years and over, but it is not unheard of for younger dogs to be diagnosed with either condition.

High Risk Dog Breeds for Thyroid Diseases

Any dog can suffer from hyperthyroidism and other thyroid conditions, but it is more common in older individuals. Some breeds appear to be more susceptible to thyroid problems, too. These include:

  • Beagles;
  • British Bulldogs;
  • Boxers;
  • Cocker Spaniels;
  • Dachshunds;
  • Doberman Pinschers;
  • Golden Retrievers;
  • Great Danes;
  • Greyhounds;
  • Labrador Retrievers;
  • Siberian Huskies;
  • Terriers.

How is Hyperthyroidism in Dogs Diagnosed?

You will be unable to properly diagnose hyperthyroidism in your pet at home. Even if your dog displays all symptoms, your vet will still need to check your furry friend over and perform diagnostic tests. These will include:

  • Ultrasound;
  • Blood tests;
  • Biopsies;
  • Physical examinations;
  • Urine tests;
  • MRIs;
  • CT scans;
  • Thyroid scans (thyroid scintigraphy).

Canine Hyperthyroidism Treatments

Your vet will determine the right course of treatment for the specific problem that your dog has.

If a mass is the case of your dog’s thyroid problem, surgery might be necessary. This can be the case for both cancerous and benign tumors. In some circumstances, surgery is not viable, and other options are called upon — chemotherapy, radiotherapy or radiation therapy, radioactive iodine therapy, and more.

If the cause is simpler, such as commercial raw food diets or supplements that contain kelp or seaweed, removing the items from your dog’s diet, plus careful monitoring, could be all that is needed.

Natural Treatments for Hyperthyroidism in Dogs

It could very well be the case that your vet recommends a natural treatment using more holistic approaches. It is not recommended to take this course of action unless specifically suggested by a medical professional.

In the event that natural treatments for hyperthyroidism in dogs do not work, the condition – and the underlying cause – is likely getting worse in the background. This could mean that underlying cancers are not being treated effectively.

Emergency Fund

If you don’t have pet insurance and are worried about the cost of vet care, it’s time for you to find out about Petcube’s Pet Emergency Fund. It’s a lifeline when you don’t have a bottom bank balance to fall back on! (Who does?!)

For less than $1 per day, up to six of your furry friends will be covered in an inclusive emergency plan, protecting any breed and age of cat or dog. With vets available online 24/7, you can even have a chat with an expert any time you’re concerned about the health of your cherished companions.

Re-think the way you do pet care with Petcube’s Emergency Fund!


How common is hyperthyroidism in dogs?

Fortunately, hyperthyroidism in dogs is quite rare. It is more common in cats in the middle-to-old age category than dogs of any age.

What happens if I take my dog off thyroid medication?

You should not withhold, reduce, or otherwise change your pet’s medication unless specifically ordered to do so by your vet. Reducing or removing medication for hyperthyroidism can cause the condition to come back, along with all symptoms — weight loss, vomiting, hyperactivity followed by inactivity, etc.

How long will a dog with hyperthyroidism live?

If you leave your dog’s hyperthyroidism problem undiagnosed and untreated, it is likely to become quite unwell quite quickly. Long-term weight loss, constipation, and excessive urination will soon cause a host of secondary problems, including bowel obstructions, malnutrition, dehydration, and more.

If you seek medical care as soon as you believe your dog is unwell, however, treatment can be swift, and your dog will have a higher chance of a full recovery.

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