Hyperthyroidism in Cats: Treatment Costs, Signs, & Symptoms

Six Minutes
Mar 02, 2023

Indoor cats can live long, happy lives, but their elusive nature can make it difficult to notice when they’re sick. Hyperthyroidism is one of the most common illnesses indoor cats can experience. And hyperthyroidism treatment can include prescriptions, surgery, or therapies that could cost anywhere from $600 – $2,700 or more.1

Here’s what you should know about the disease, including how it’s diagnosed and a breakdown of treatment costs.

What Is Hyperthyroidism in Cats?

Feline hyperthyroidism is caused by the overproduction of hormones from a cat’s thyroid gland.2 Thyroid glands are a pair of butterfly-shaped glands located on either side of the windpipe. This affliction is one of the most common hormonal disorders in middle-aged and senior cats.

Hyperthyroidism is usually caused by a benign tumor that produces excess thyroid hormones on one or both thyroid glands. Most cases of hyperthyroidism are mild, with many cats not showing any signs of the illness.2

Hyperthyroidism in Cats: Treatment Costs

The cost of treating hyperthyroidism varies depending on which options you and your vet decide to pursue as well as where you live, your cat’s specific case, and the vet you see. Here are some average prices you may pay for hyperthyroidism treatment:1

  • Prescription diet: Up to $1,200 per year
  • Medication: $600 – $900 per year (includes regular exams and tests to monitor progress)
  • Radioactive iodine therapy: $1,200 – $2,700 (includes treatment and hospitalization)
  • Surgery: $1,800 – $2,500 per surgery

It’s important to keep in mind that a cat with hyperthyroidism may require multiple forms of treatment. For example, surgery and radioactive iodine therapy could be prescribed in tandem. Your cat may also need multiple rounds of surgery depending on the number of tumors present.

Cat insurance can help shoulder the cost of treatment. However, it’s important to insure your cat as early as possible in their life to avoid coverage exclusion for pre-existing conditions.

Hyperthyroidism in Cats: Symptoms

Cats who do experience symptoms of hyperthyroidism are usually 8 years old or older. Your cat may exhibit one, some, or even all of the symptoms associated with it, which can make it difficult for pet parents to diagnose it on their own.

The most common hyperthyroidism symptoms in cats can include:2

  • Weight loss
  • Excessive appetite
  • Increased urination and thirst
  • Vomiting
  • Diarrhea or increased fecal volume
  • Hypersensitivity
  • Unruly or unkempt fur

Some other signs of hyperthyroidism in cats can be heart issues, which can include:2

  • Increased heart rate
  • Heart murmurs
  • Shortness of breath
  • An enlarged heart
  • Congestive heart failure

Keep in mind that hyperthyroidism can be a progressive disease. That means that it may take several years for a cat to experience complications from hyperthyroidism.

Because you may notice common symptoms, such as rapid weight loss and diarrhea, addressing them will usually have you scheduling a vet visit long before heart complications could set in.

Diagnosing Hypothyroidism in Cats

To diagnose hyperthyroidism, your vet may perform a physical exam that focuses on your cat’s throat.2 They’ll look for any lumps or masses that may indicate a tumor is present. After the exam is done, your vet should discuss behavior that you’ve noticed at home — such as vomiting or weight loss.

Lastly, your cat’s hormones will usually be measured using a common blood test. This test will measure the amounts of T3 and T4 (iodine-containing hormones) in your cat’s blood sample.2 Depending on your veterinarian’s office, it’s likely that the test can be done in-house, so you might get the test results quickly. That said, it might still take a few days for the sample to be thoroughly tested and examined.

How To Treat Hyperthyroidism in Cats

Vets may choose to manage the hormonal disorder with simple lifestyle changes, medications, surgery, or a combination of all these approaches. Here’s what treatment of hyperthyroidism in cats could look like.

Lifestyle changes

Once you’ve received your diagnosis, your vet can work with your family on lifestyle changes to gain control of hyperthyroidism. This may involve feeding your cat a specialty diet. Hyperthyroidism diets are low in iodine — which can help minimize their symptoms — and typically given to them for the rest of their life.2

Your vet may also encourage you to give your cat more exercise. Talk to your vet about ways to boost your pet’s energy levels or manage their playtime throughout the day.

Medications and therapy

Medications for hyperthyroidism in cats are prescribed on a case-by-case basis. Currently, there’s only one FDA-approved medication to treat feline hyperthyroidism called methimazole.2,3 The dosage may vary, but typically a cat is given this oral medication twice a day every 12 hours.2,3

Another option may be radioactive iodine therapy, which works by injecting iodine into the thyroid glands, destroying the overactive tissues.2 This method is often considered safe, simple, and effective for most cats.


Your vet may suggest surgically removing the affected thyroid glands.2 Some cats don’t qualify for surgery because of their age and health. For example, if your cat has liver disease and they’re diagnosed with hyperthyroidism, your vet may think it’s too risky to perform surgery.

The reason? If parts of both glands or all of the glands are removed, your pet will have to take hormone replacements for the rest of their life.1 These hormonal medications have side effects that can impact their lifestyle and how well their organs function. It’s recommended to weigh your pros and cons with your vet before deciding to move forward with such a procedure.

Pet Insurance Can Help With Treatment Costs

Hyperthyroidism can be a scary disease for pet parents, and it becomes more common as cats enter their golden years. Luckily, hyperthyroidism in cats is common and treatable, so vets across the country are ready and able to help you care for your pet. MetLife Pet is also here to help you give your cat the care they need with pet insurance that can reimburse you for covered costs. Get started today with a free quote today.

Help Protect Your Cat from Illnesses

**As with any insurance policy, coverage may vary. Review our coverage and exclusions.

1 “Pricing and Payments,” Cat Thyroid Center

2 “Disorders of the Thyroid Gland in Cats,” Merck Veterinary Manual

3 “Hyperthyroidism in Cats —There’s an FDA-Approved Drug to Treat It,” Federal Drug Administration

Coverage issued by Metropolitan General Insurance Company (“MetGen”), a Rhode Island insurance company, headquartered at 700 Quaker Lane, Warwick, RI 02886, and Independence American Insurance Company (“IAIC”), a Delaware insurance company, headquartered at 11333 N Scottsdale Rd, Ste 160, Scottsdale, AZ 85454. Coverage subject to restrictions, exclusions and limitations and application is subject to underwriting. See policy or contact MetLife Pet Insurance Solutions LLC (“MetLife Pet”) for details. MetLife Pet is the policy administrator. It may operate under an alternate or fictitious name in certain jurisdictions, including MetLife Pet Insurance Services LLC (New York and Minnesota) and MetLife Pet Insurance Solutions Agency LLC (Illinois).

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