Feline Hyperthyroidism: Can You Treat It Naturally?

feline hyperthyroidism treat naturally boulderholisticvet blog post

As a holistic veterinarian, I am often approached by cat parents who are looking for a more natural approach to hyperthyroidism in their kitties. If you do a quick Google search on Methimazole (the oral medication commonly used to treat hyperthyroidism), it’s perfectly understandable why guardians are apprehensive about long term use of this drug. It’s important to understand that Methimazole is not the only treatment for this common condition. In this article, I will discuss the basics of hyperthyroidism in cats, what may be the underlying cause, and how I treat cats in my practice.

The Basics

Hyperthyroidism is the most common hormonal imbalance in senior cats. This occurs when the thyroid gland becomes enlarged and produces more thyroid hormone. The excessive amount of thyroid hormone causes weight loss, increased liver enzymes, vomiting, heart disease, and excitability/anxiety.

The majority of cases are easy to diagnose with a simple blood test of a total T4. On occasion, some cats may have a borderline T4 value, with vague symptoms. These kitties may require further diagnostics.

The Cause

Hyperthyroidism in cats is a relatively new disease, becoming much more prevalent only within the past 40 years. There has been much speculation within the veterinary community about what may have caused this increase in disease, and more research is needed. Culprits with the most evidence include fire retardants used in building materials and furniture. Additionally, there is some evidence that the products used to line canned food may also be linked to this hormonal imbalance. A genetic predisposition is also likely required.


There are three traditional therapies available for hyperthyroidism:

  1. Methimazole
  2. Iodine Therapy
  3. Thyroidectomy

Thyroidectomy, the surgical removal of the thyroid gland, is rarely performed. For this article, the focus will remain with Methimazole and iodine therapy.


Methimazole is the most commonly recommended treatment. This drug works by interfering with the thyroid’s ability to make thyroid hormone. It is given either orally, or is absorbed through the skin (usually applied to the ear). While this drug is generally well tolerated, it can cause vomiting and lethargy in a subset of cats. On occasion, there are some cats that don’t respond to the Methimazole at all. Over the ten years that I have been practicing, I have seen this a handful of times, including with my own cat.

Pros: Methimazole is a relatively inexpensive treatment that can be extremely effective. Most cats feel great once their thyroid gland is regulating appropriately, and symptoms resolve within a couple months. If your cat is not interested in taking a tablet everyday, the transdermal cream can be placed on the ear twice daily and is a relatively easy option.

Cons: Your kitty will need medication everyday for the rest of his/her life.  During the initial stages, your cat will need to have bloodwork done every 4-6 weeks, until the correct dosage has been reached. Generally, this is achieved on the first or second try. After the correct dosage is found, bloodwork should be rechecked every 6 months thereafter, to make sure thyroid levels are maintaining appropriately.

It should also be noted that some cats do not properly absorb the transdermal form of methimazole, and require oral dosing only.

Iodine Therapy

This therapy involves the use of radioactive I-131. This may sound like the furthest thing from natural medicine, but keep reading! Iodine therapy has many advantages, and is considered the gold standard for treatment. I usually recommend this option as first line therapy. It is generally performed at a specialized facility, and involves only one treatment of iodine (I-131). I-131 specifically targets the thyroid gland, while sparing the surrounding structures (including the parathyroid glands). It is non-invasive, and requires only a few days of hospitalization to allow the radioactive particles to degrade. One set of follow up blood tests are required, and most cats are then cured for life!

Pros: One treatment is almost always curative, and no daily medication is required. It is extremely non-invasive, and you will not have to medicate your cat twice daily for the rest of their lives.

Cons: This is initially a more expensive treatment. In the state of Colorado, you can expect to spend $1,500 – $2,000. Treating with Methimazole, in addition to the maintenance blood tests required, will cost that (or more) over the span of several years. However, those costs are more spread out.

You will also spend at least four nights away from your kitty during treatment. This was the hardest part for me!

Diet Therapy

There is a prescription diet by Hills, that contains extremely low levels of iodine. This diet therapy can work, but has a couple of limitations. The palatability is poor, and many cats will not eat the diet. It can only work if it is the sole diet given, no other treats or foods allowed. Even a few bites of another food would exceed the iodine restriction threshold. This food is also low in protein, and can cause muscle wasting.

Hyperthyroidism and Kidney Disease

It is important to note that hyperthyroidism will cover up kidney disease. This occurs because the overactive thyroid hormone increases blood flow to the kidneys. When hyperthyroidism is treated, and blood flow returns to normal, the true kidney function is uncovered. Kidney disease is very common in older cats, and therefore most hyperthyroid cats have some degree of kidney disease as well.

Once treatment begins, expect that your kitty’s kidney values will rise. It is important to understand that the kidney disease was not caused by the treatment but, instead was present all along.

You can learn more about my holistic approach to kidney disease here.

Natural Treatments

Over the years, I have had little to no success using herbs and other alternative therapies to reverse thyroid disease in cats. I believe that this is one instance when traditional therapy has the best answer.

Ideally, I would like to go back in time – clean up all the environmental pollutants, and take flame retardants out of everything! Going forward with the knowledge we have today, we can all make better choices for our cat’s environment. This includes purchasing furniture without fire retardants, using better building materials, and choosing non-toxic cleaners.

For now, and if finances allow, I recommend the iodine therapy first.

Wishing you and your feline friends health and happiness!

With love,
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25 thoughts on “Feline Hyperthyroidism: Can You Treat It Naturally?”

  1. I’ve used Hyper Jia Bing with two of my hyperthyroid cats. It returned one of my hyperthyroid cats to a non hyperthyroid state for the time being. The other one is on a very low dose of transdermal methimazole which has worked out very well for him. The “hyperthyroid” food is very misleading, as it presents its deleterious health effects, and he is not a good candidate for the i-131 because of his kidney values. They both receive a quarter of a scoop twice a day (the scoop comes in the jar).
    I purchase the product from our functional medicine veterinarian in North Carolina, however, the brand name is Jin Tang. It is distributed by Dr. Xie’s Jin Tang Herbal, Inc.
    Web: http://www.tcvmherbal.com

  2. Thank you for sharing this. In my process during this time and research process, I have tried unsalted bone broth with my cat and he loves it too and it satisfies him when mixed with chicken.

    It is good to know that you have given him this REAL food as well as the Hill’s diet, despite instruction to exclusively serve Hill”s diet forever and that has been okay and not undermining the effectiveness of the Hill’s program.

    1. I have a cat with hyperthyroidism and tried first the Methimazole pills, which she couldn’t tolerate after two weeks; then I tried the same only using the transdermal method twice a day. That didn’t work either. I’m down to trying delivery of just once a day now to see how that works. I don’t have much confidence it will because she has vomited several times early this morning and later in the day.
      I’m very interested in the unsalted bone broth and raw meat. I’ve been feeding my cats Friskies canned wet food plus Purina “natural” kibble. I want to change their diet but need help. I’m going to start with the bone broth. Is there any particular brand that is better? I’m also going to try the raw chicken/beef method.

      1. Hi Barbara,

        We very recently had a cat in Dr. Angie’s practice that did not respond to the I-131 treatment (UGH!) or the Methimazole. However, has a completely normal T4 now on an Rx diet (Science Diet YD for hyperthyroidism). Rx diets are not something we often promote, but it has been life-changing for this kitty!

        As far as bone broth, have you seen Dr. Angie’s bone broth recipe here?

        I hope this helps! Please keep us posted!


  3. My cat is living proof that hyperthyroidism can be successfully treated with a low-iodine diet. My cat was diagnosed with hyperthyroidism at age 13, after a year and a half of eating a cat food that was “guaranteed” to cause weight loss. Yes, he had lost weight on that stuff, but he’d become very ill, too: he was vomiting several times a day, anxious and yowling all the time, drinking and peeing great volumes of water, was too weak to jump up on a sofa, he even got aggressive with me sometimes. The vet also said his heart rate was dangerously fast, and he was dehydrated despite all the water he drank. I learned later that the weight-loss cat food he’d been eating contained excessive iodine, which likely over-stimulated his thyroid gland and caused thyroid tumors. When the vet told me the treatment options I balked: either surgically remove his thyroid gland and give him thyroid hormone supplements the rest of his life, or give him anti-thyroid medication the rest of his life. Either would require many expensive vet visits to adjust his thyroid hormone levels until he was stable. I said no to both. I decided instead to try to cut iodine out of his diet. As soon as I changed his diet he stopped vomiting, and over the next several months all his other symptoms cleared up. The iodine-restricted diet meant no fish or seafood, no salted human foods because table salt is usually iodized, and no cat food containing iodine supplements in the form of kelp, potassium iodide or calcium iodate. I read all the cat food labels and at first I could not find ANY cat food that didn’t contain either fish or iodine supplements, or both. So I fed him raw poultry and unsalted bone broth. (My reasoning was that cats evolved eating whole animals including bones, and raw meat was only muscle, so I assumed bone broth should contain some calcium or whatever is in bones that he needs.) Eventually I found Hill’s prescription low-iodine YD food, and this is mainly what he’s been eating for almost 2 years now. I also give him raw ground chicken or turkey a couple of times a week, and unsalted bone broth every day because he loves it. He’s now 15 — and in perfect health! He recently had blood work done and all his blood levels are normal, including his thyroid hormone level. The vet said she’d never heard of treating hyperthyroidism with diet alone, but said I should keep doing what I’m doing because it’s clearly working.
    Please consider that the cause of so much hyperthyroidism in cats may be the iodine supplements in cat foods. Ans please recommend that your clients try a low-iodine diet before more drastic treatments.

    1. Hi Marcy,

      THANK YOU so much for sharing your experience!

      We have a kitty in the practice (currently) who is finding relief from his hyperthyroidism using just a low-iodine diet as well. He failed all other treatments and this diet is the ticket to his health.

      I appreciate your thoughtful response and am so glad your kitty is feeling better!


    2. Janna E Gelfand

      Congratulations for figuring this out and THANK YOU SO MUCH for sharing it!!!! Are you comfortable with sharing where you buy the bone broth? Is there any special type you use? I’ve not dealt with it before and I want to do this correctly. Thank you so much again!!!! Janna :o)

    3. Marcy,

      Wow! Reading your post gives me some much needed hope! My kitty is 11 1/ 2 and was diagnosed with hyperthyroid officially over a year ago. I’ve tried methimazole (I find it makes her vomit more and her appetite is worse and she’s just so unhappy and lethargic). I’ve found 2 homeopathic vets in my area (New York City) and have tried those remedies without much success – she continues to lose weight and drinks/pees excessively. I’ve been making the majority of her food the past few months in combination with some herbal supplements I just started – Resthyro from NHV Natural Pet Products seems to be helpful, at least for her mood. She seems to fare pretty well when her appetite is good, but I’m at wits end here! I just connected with a center here who performs the I-31 radio iodine treatment, but am nervous about it and the traditional vet where she had her blood work done wants her to go back on methimazole (which raised her kidney levels the last time we tried it).
      I’m going to try the unsalted bone broth and chicken and see how fares on that and keep on with the food I’ve been making her (adding taurine and a kidney supplement called AminAvast).
      Any other advice, even just moral support, would be greatly appreciated! Coco is my best friend and I’m so sad for her every day!!


  4. With dietary options, I am curious about a somewhat homemade raw food/species appropriate diet. Just like commercially developed food for humans is known to cause modern day diseases, I suspect this could be the same for felines. Even so-called healthy ‘grain-free’ kibble has items added such as kelp which is loaded with iodine, and I am sure it is salted with iodized salt. The Science Diet ‘Thyroid Care’ formula has ‘corn and soy,’ which I do not believe to be species appropriate diet for felines. Cats do not feast on corn and soy in the wild, but both grains do have a negative effect on the human thyroid due to lectins in the corn, and phytoestrogens in the soy…so maybe this is helpful with with down-regulating thyroid hormones in felines. Anyways, with this train of thought, I am just wondering if modern day cat food could be the cause, and if a raw cat food diet could possibly be a forth option to look into.

    1. Hi Bill,

      These are GREAT thoughts, and I really think you are on to something here.

      We know we’ve been feeding cats all wrong for many years. This is slowly becoming accepted knowledge in the veterinary community. I think that as the years progress, we will continue to learn how to feed our cats better including promoting healthy, more species-appropriate diets like canned or raw foods!

      Thank you for your thoughts!


    1. Hi Julia,

      I will love hearing the answers that you hopefully get for this question!

      Unfortunately, in Dr. Angie’s practice, we have not had success treating hyperthyroidism with CBD. We did recently have a kitty in the practice fail the I-131 treatment (only 2% of kitties fail this!). In addition, he did not respond to daily medication or Chinese herbs. However, respond exceedingly well to a prescription thyroid diet. We do not usually endorse these diets, but this was one time where we say the thyroid levels return to normal after 1 year of feeding!

      I hope this helps!


    1. Thank you for sharing this. In my process during this time and research process, I have tried unsalted bone broth with my cat and he loves it too and it satisfies him when mixed with chicken.

      It is good to know that you have given him this REAL food as well as the Hill’s diet, despite instruction to exclusively serve Hill”s diet forever and that has been okay and not undermining the effectiveness of the Hill’s program.

  5. Hi there, thanks for the information! Have you tried treating many cats herbally for thyroid disease? I hope that doesn’t sound condescending! I am curious as a western herbalist with absolutely no experience in this and seeking some guidance for my own cat and would love any suggestions and specific experiences treating herbally you have had in your practice. Thanks a bunch!!

  6. What are the dosages for a 13 year old 8 lb cat for your following recommended meds?

    Fish Oil. I use high doses of fish oil to help reduce inflammation and recommend Nordic Naturals.
    Rx Renal by Rx Vitamins for Pets. This is a great blend of herbs that help improve kidney function.
    Probiotics. I use Rx Biotic by Rx Vitamins for Pets. Probiotics can help improve digestion and reduce inflammation.

    1. Dr. Angie Krause, DVM

      Hi Glen,

      Good questions.

      Here is the dosing for the following:
      1) Nordic Natural fish oils – 0.5 mL (78 mg EPA/46 mg DHA) daily (this is their recommendation, you can likely increase from here and then back down the dosing if your kitty is experiencing vomiting or diarrhea).
      2) Rx Renal – one capsule twice daily.
      3) Rx Biotic – 1/2-1 scoop daily.

      I hope this helps!


  7. You need to try Hyper Jia Bing, a Chinese herbal for hyperthyroidism. I have used it on many cats. They eat it mixed in food, it relieves many of the symptoms and in one case the thyroid values returned to normal.

    1. Dr. Angie Krause, DVM

      Hi Dr. Stange,

      Thank you so much for this information! I passed it along to Dr. Angie, and she would love to give you a call to chat more.

      You will hear from her soon!


    2. Hi Dr Stange,
      I have a 17 yo old cat who can’t tolerate methimazole. What is the dosage you use for Jia Bing, and where can I purchase it? Thank you!

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