Hyperthyroidism in cats goes by a couple of different names, so you might have heard it referred to as thyrotoxicosis or thyroid disease. It is somewhat of a “silent” disease, plodding along quietly and silently, not causing any problems, until one day it makes your feline friend rather unwell.

Knowing the symptoms of hyperthyroidism in cats is important. Treatment has a much higher success rate when administered at an early point.


  1. What is Hyperthyroidism in Cats?
  2. Symptoms of Cats With Hyperthyroidism
  3. What Are the Signs Your Cat is Dying of Thyroid Disease?
  4. Worried About Vet Costs?
  5. 4 Options for Cat Thyroid Medication and Treatment
  6. Are There Natural Treatments for Hyperthyroidism in Cats?
  7. Cat Hyperthyroidism Life Expectancy
  8. FAQ

What is Hyperthyroidism in Cats?

A cat with hyperthyroidism has one or more overactive thyroid glands. There are two of these glands, located on either side of your cat’s windpipe, and they are responsible for keeping your cat's metabolism in check.

In the case of hyperthyroidism, too many hormones are produced by the thyroid glands.

Cats can also suffer from hypothyroidism, which is the opposite problem. The thyroid gland is underactive and doesn’t produce enough hormones.

Symptoms of Cats With Hyperthyroidism

Sadly, cats with hyperthyroidism can display very few symptoms of their condition until the condition has progressed significantly, at which point it can be fatal.

According to research, symptoms that are commonly associated with hyperthyroidism (particularly late hyperthyroidism) in cats include:

You might also be able to feel the enlarged thyroid glands in the neck, although they are usually quite small.

What Are the Signs Your Cat is Dying of Thyroid Disease?

Many of the symptoms listed above will not materialize until the disease has progressed significantly in your pet, but even late-stage hyperthyroidism cases can be successfully treated. In fact, there are a minimum of four treatment approaches that can be used to treat this condition at all stages — and at least one of them has a success rate of 98%.

If you believe your cat is acting unusually, trust your gut instinct and get in touch with a vet. You know your pet better than anyone else, so if you believe that something is wrong, it is always better to be safe rather than sorry.

Worried About Vet Costs?

If you’re concerned about how much getting your cat checked by a vet will cost you, why not take a look at the Emergency Fund offered by Petcube?

For less than the price of a trip to the movies for two, you’ll get access to up to $3,000 of veterinary care, when you need it the most. And that’s not all you’ll get. You’ll also unlock 24-7 access to professional, fully-trained vets – all from the comfort of your very own couch.

4 Options for Cat Thyroid Medication and Treatment

Vets will usually use four treatments for hyperthyroidism: dietary therapy, medication, surgery, and radioactive iodine therapy.

The correct course of treatment will depend on a wide variety of factors, including the specific hormones that are disrupted, the levels of those hormones, and other symptoms displayed by your pet.

1. Cat Diet For Hyperthyroidism

Dietary therapy for cats with hyperthyroidism usually involves restricting the amount of iodine that they have in their diet. The approach has been met with criticism, with some studies showing that iodine restriction can be just as dangerous to your pet as hyperthyroidism itself.

This will usually be an option chosen when other methods are not appropriate, perhaps due to other medical conditions.

2: Cat Thyroid Medicine

Cat medication for hyperthyroidism will not cure the condition, but it can help to manage it, prolonging the life of your pet and ensuring they are not in pain and discomfort.

There are pros and cons to using medication to achieve normal thyroid levels in cats. Your cat will require the medication for the rest of its life (in most cases), which can be quite costly over time. Some owners have found the number of doses per day quite difficult to keep up with, too.

These are all factors that will need to be discussed with your vet.

3: Radioactive Iodine Treatment for Hyperthyroidism in Cats

For many vets, this is the treatment of choice for hyperthyroidism in cats, although it isn’t always readily available. Nor is it convenient for all pets, or pet owners.

Cats that receive radioactive iodine treatment will need to stay in the vet’s surgery for the duration of their treatment, which can be up to a week in some cases. It can only be performed by specially trained professionals, too. Being radioactive, the treatment comes with its fair share of challenges and dangers.

One of the best things about using this type of treatment for cats with hyperthyroidism is that it can actually help to cure the condition, rather than just manage it. This means that your pet is likely to only need one ‘round’ of treatment, rather than a steady and prolonged course of medication. More than one round can be administered if necessary, however.

This treatment for cat hyperthyroidism can cause hypothyroidism – the opposite of hyperthyroidism, although this is, thankfully, rare.

Other cons of this feline hyperthyroidism treatment include not being able to cuddle with your cat for a period of three weeks after treatment, keeping multiple cats separate, keeping your pet inside the home, and more. This will all be explained to you by your vet prior to treatment starting.

4: Surgical Thyroidectomy for Hyperthyroidism in Cats

Surgery isn’t a great treatment for cats with existing medical conditions that affect the kidneys or heart, overweight cats, or older cats, but it can still provide a permanent cure for the condition in younger cats with otherwise good health.

With hyperthyroid cat surgery, the thyroid glands are removed entirely, under a general anesthetic. These glands are close to other vital glands, however, such as the parathyroid glands. If these are damaged during the surgery, there can be problems with calcium levels in the blood. Because of this, surgery is often the last resort for cats with thyroid disease.

Are There Natural Treatments for Hyperthyroidism in Cats?

It is not recommended to try natural treatments for hyperthyroidism in cats unless you have been given the go-ahead by your vet.

This condition can - and will - be very dangerous when untreated, and some natural treatments are not treatments at all, in the sense that they likely won’t work. All the while the natural hyperthyroidism treatments are not working, and your cat’s health will be in decline.

Some natural remedies for hyperthyroidism in cats are: switching to organic/all-natural cat food types, supplementing the diet with various minerals and vitamins, and even going as far as switching from commercial to raw cat food. These may be recommended by your vet to work in conjunction with other treatment approaches, such as medication or surgery.

Cat Hyperthyroidism Life Expectancy

Hyperthyroidism in cats that is not treated, is almost always fatal. This is because of the effect the hormone disruption eventually has on all of the other vital organs in the body.

Cats with hyperthyroidism that are given the appropriate treatment can lead long, happy, and fulfilling lives without any reduction in lifespan. Radioactive iodine treatment, for example, has a very high cure rate after one or two rounds of treatment – 95% to 98%.

The sooner you have your cat diagnosed and treated, the higher the chances of your cat being 100% cured.


How Long Can a Cat Live with Hyperthyroidism?

Cats can live very long and healthy lives if they receive the appropriate treatment for their specific case of hyperthyroidism. Treatment is not a one-size-fits-all situation, but a vet will come up with a treatment plan that combats all symptoms and aspects of your cat’s condition.

What to Feed a Cat with Hyperthyroidism?

Your vet may recommend a change in diet for a cat with hyperthyroidism, although this is usually not a first-resort treatment approach. Some dietary changes include switching to a specific, low-iodine type of cat food; replacing regular cat food with raw cat food; and using vitamin and mineral supplements. These changes should not be made unless recommended by a vet.

What Happens if Cat Hyperthyroidism is Untreated?

Hyperthyroidism in cats is a potentially deadly condition if left untreated. An afflicted feline is likely to lose a lot of weight, have serious digestive issues, and act unusually - often aggressively.

Over time, hyperthyroidism causes damage to vital internal organs, which will eventually lead to death. If you suspect your cat has hyperthyroidism, it is vital that you get them checked over by a vet.

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