Best Cat Food For Hyperthyroidism

Medically reviewed by JoAnna Pendergrass, DVM
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The thyroid glands are small, oblong-shaped glands located on either side of the neck. These glands produce thyroid hormones—thyroxine (T4) and triiodothyronine (T3)—and regulate the body’s metabolism.

Hyperthyroidism is the overactivity of the thyroid glands. It is most commonly caused by a benign tumor, called an adenoma. Rarely, hyperthyroidism in cats is caused by a carcinoma, which is a malignant tumor.

Overproduction of thyroid hormones affects the central nervous system, gastrointestinal system, heart, liver, and kidneys. The overactive metabolism burns up fuel faster than your cat can eat it, resulting in muscle wasting and significant weight loss, leading to emaciation.

Hyperthyroidism can be treated in several ways. Thyroidectomy is the surgical removal of the thyroid glands. Radioiodine treatment uses radioactive iodine to destroy the overactive thyroid gland and normalize thyroid hormone production. There is also medication that is given lifelong to inhibit thyroid hormone production.

Without proper treatment, hyperthyroidism is usually progressive and may be fatal. Click here to learn more about your treatment options.

The best cat food for hyperthyroidism is rich in species-appropriate protein, low-carbohydrate, and is free from ingredients that contribute to thyroid disease. Management of iodine, which plays a role in thyroid hormone production, can also help.

Because it’s the only food on the market that’s formulated to reduce hyperthyroidism symptoms, we’ve chosen Hill’s Prescription Diet y/d Thyroid Care as the best cat food for hyperthyroidism.

In addition to this Hill’s formula, our list includes four non-prescription products. They won’t treat hyperthyroidism, but they may help your cat feel better before and after medical treatment.

Food is not a cure for hyperthyroidism, but the right diet can help your cat maintain or regain muscle mass and may ensure good health after treatment.

At A Glance: Best Cat Food For Hyperthyroidism To Buy

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Want a quick look at the products reviewed in this article? In the comparison table below, we’ve highlighted some of the most important features of each product. You’ll find more detailed information about each product later in the article.

Overall Best
10.0
Picked by 31 people today!

Hill’s Prescription Diet Thyroid Care y/d Feline Canned

  • Inhibits excessive thyroid hormone production
  • Cats tend to like the taste of the food
  • A healthier alternative to the y/d dry food
Best Non-Prescription Pick
9.8
Picked by 31 people today!

Smalls Fresh Bird Cat Food

  • Shipped to your door with custom meal plans
  • Single source of high-quality animal protein
  • Low in carbohydrate content
Best Dry
9.5
Picked by 25 people today!

Hill’s Prescription Diet y/d Thyroid Care Original Dry Cat Food

  • Can help to control the symptoms of hyperthyroidism
  • Cats like the way this food tastes
Best for Sensitive Stomach
9.4
Picked by 21 people today!

Instinct by Nature’s Variety Original Grain-Free Real Lamb Recipe

  • High in moisture
  • Rich in biologically appropriate animal protein
  • Low in carbohydrates
Budget Pick
9.3
Picked by 18 people today!

Wellness Complete Health Pate Chicken Entreé

  • One of the best values on the market
  • Doesn’t contain soy or other ingredients that might worsen thyroid function
  • Rich in nourishing animal protein
Best for Seniors
9.2
Picked by 31 people today!

Feline Natural Chicken & Venison Feast Cat Food

  • Addresses multiple conditions common among senior cats
  • Rich in highly-digestible animal protein for sustained muscle mass
  • Low carbohydrate content is ideal for insulin-resistant cats

What To Look For In The Best Cat Food For Hyperthyroidism?

Hyperthyroid Cats Need Highly-Digestible Protein.

Hyperthyroid cats have two things working against them when it comes to maintaining muscle mass. First, they have an overactive metabolism. Secondly, most of them are seniors.

New research suggests that seniors have high protein and energy needs—similar to the needs of kittens. When these needs aren’t met, they lose muscle.

Choose foods with over 50% of calories from protein. The best protein sources are species-appropriate and highly digestible. As an obligate carnivore, your cat requires meat-based food with no high-protein fillers like pea protein, potato protein, wheat gluten, and corn gluten meal.

Choose A Diet That’s Less Than 10% Carbohydrate On A Dry Matter Basis.

Hyperthyroidism raises your cat’s blood glucose levels and often leads to insulin resistance and impaired glucose tolerance. This is a prediabetic state. Even if this doesn’t advance to full diabetes mellitus, hyperthyroid cats are sensitive to sugar and require controlled levels of dietary carbohydrates.

What To Avoid When Feeding A Hyperthyroid Cat?

Avoid Fish-Based Foods.

A study in 2000 found that cats who preferred canned cat food in fish or liver and giblets flavors had an increased risk of hyperthyroidism. Fish and other ocean creatures have higher levels of iodine than are found in other foods. Since iodine is central to thyroid function, this may be part of the connection, but it’s not clear that iodine content is the only problem. Talk with your veterinarian if you are concerned that your cat’s canned food diet is increasing the risk of hyperthyroidism.

Most Fish Is Contaminated With Toxins, Including PBDEs

These fire-retardant chemicals were extremely popular in the late 1970s and were used to treat everything from pajamas to curtains. Because they’re known endocrine disruptors, PBDEs were essentially phased out in the United States and European Union during the early 2000s. That doesn’t mean they’re not still everywhere. These toxins linger in soil, dust, waterways, human bodies, and the ocean — they’re present in cans of fish-based food.

According to a study published in 2017, PBDE levels in the blood were higher in hyperthyroid cats than in healthy cats. This study also noted that PBDEs disrupt thyroid function and may contribute to hyperthyroidism in cats.

If Feeding Canned Food, Ensure That The Can Is BPA-Free.

Cats who eat canned foods, particularly cans with pop-top lids, have an increased risk of thyroid problems. Cat food cans are often coated with an epoxy lining containing BPA. BPA acts as a thyroid receptor antagonist and alters thyroid function.

Don’t Feed Your Cat Soy

Soy disrupts normal thyroid functioning. A soy-containing diet may increase a cat’s risk of developing hyperthyroidism.

When researchers gave 18 healthy adult cats either a soy or soy-free diet for three months, they found that the cats who ate a soy diet ended the study with “significantly higher total thyroxine (T4) and free T4 (fT4) concentrations, but unchanged total triiodothyronine (T3) concentrations.”

The soy-based diet had a small, but significant effect on the amount of thyroid hormone produced by the body.

Select A Low-Iodine Diet

Iodine plays a role in thyroid hormone production. Therefore, a cat with hyperthyroidism should eat a low-iodine diet to ensure that the overactive thyroid glands aren’t being stimulated to produce even more thyroid hormone.

Should You Feed Your Cat A Prescription Diet For Hyperthyroidism?

Hill’s Prescription Diet y/d is the leading prescription cat food for hyperthyroidism. This food is extremely low in iodine, containing less than 0.32 ppm iodine on a dry matter basis.

In the paper linked above, the writer notes that as of 2011—when the article was written—“all hyperthyroid cats managed with Hill’s Prescription Diet® y/d® Feline as the sole source of nutrition have become and remained euthyroid (having normal thyroid function) as long as the cat had no access to other sources of iodine.”

A low-iodine diet cuts off the supply of iodine, slowing thyroid hormone synthesis. It does not fix an enlarged thyroid gland, nor does it prevent an adenoma from changing into a carcinoma. It only reduces the symptoms of hyperthyroidism.

How Much Iodine Does A Normal Cat Require?

Given the diversity of iodine concentration in homemade, commercially-available, and wild-caught food, it’s difficult to identify how much iodine cats require.

In 2006, the National Research Council suggested that the dietary iodine requirement for cats was 1.3 ppm. Newer research conducted by Hill’s Pet Nutrition suggests that the requirement may actually be closer to 0.46 ppm.

The 0.32 ppm iodine in the Hill’s diet is low. While it’s currently thought that iodine is used only for thyroid hormone synthesis, we ultimately don’t know how an iodine-restricted diet will affect long-term health.

Because it’s restrictive, not species-appropriate, and isn’t a real cure, think of this diet as a temporary measure or as a last resort for cats who can’t undergo surgery or receive radioiodine therapy.

In addition to performing our own qualitative analysis of the brands reviewed here, we submitted samples for analysis at an ISO 17025 certified food testing and analysis lab.

We bought the products at full retail price, and the entire testing process was funded by All About Cats without direct input or influence from the companies involved.

Analytical testing in a food chemistry lab gives us the exact macronutrient and
micronutrient content of each recipe. The tests also look at microbial content, yeast, mold, and heavy metals, helping you ensure that you’re only putting the best in your cat’s bowl.

To access the lab reports for each food reviewed here, click the “view lab report” link in the product review.

Top 6 Best Cat Foods For Hyperthyroidism

Because they’re typically lower in carbohydrates, usually contain higher-quality protein, and are more hydrating than dry foods, all but one of the products on the following list are wet cat foods; Hill’s Prescription y/d dry cat food is the only dry cat food that made our list.

With the exception of the Hill’s prescription diet, these are not treatments for hyperthyroidism. Instead, they contain high levels of highly-digestible protein to maintain and restore lean muscle mass. These foods should accompany curative treatment.

If your cat has any concurrent diseases that demand a special diet, consider those needs first and talk to your veterinarian to find a food that encourages all-around good health.

#1 Overall Best: Hill’s Prescription Diet Thyroid Care y/d Feline Canned Review

Hill's Prescription Diet y/d Thyroid Care with Chicken Canned Cat Food

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First 5 Ingredients: Water, Pork Liver, Pork By-Products, Chicken, Corn Flour

While this food is pushed as an alternative to lifelong medication, radioiodine treatment, or a thyroidotomy, it’s not a cure for hyperthyroidism.

It starves the thyroid of fuel, but it doesn’t slow down the progression of a thyroid tumor. The adenoma (benign tumor) will continue to grow and potentially change into a carcinoma.

A cat on this diet will have to eat it for the rest of their life to prevent a relapse of their symptoms. They can’t eat any other foods, including therapeutic foods specific to common conditions like chronic kidney disease, diabetes, or pancreatitis.

Lastly, the food is a high-carbohydrate, low-protein diet. The canned food is about 27% protein, 24% carbohydrate, and 49% fat. This isn’t an ideal calorie distribution for any cat, much less a senior with a propensity to lose muscle mass. Senior cats require high-quality protein to maintain healthy muscle mass, and this diet just doesn’t offer what they need.

Ingredients:

Water, Pork Liver, Pork By-Products, Chicken, Corn Flour, Rice, Chicken Fat, Chicken Liver Flavor, Powdered Cellulose, Calcium Carbonate, Fish Oil, Natural Flavor, L-Lysine, Potassium Chloride, DL-Methionine, vitamins (Vitamin E Supplement, Thiamine Mononitrate, Ascorbic Acid (source of Vitamin C), Niacin Supplement, Pyridoxine Hydrochloride, Calcium Pantothenate, Vitamin B12 Supplement, Riboflavin Supplement, Folic Acid, Vitamin D3 Supplement, Biotin), Guar Gum, Taurine, Choline Chloride, Salt, Cysteine, Dicalcium Phosphate, L-Carnitine, minerals (Ferrous Sulfate, Zinc Oxide, Copper Sulfate, Manganese Sulfate), Beta-Carotene.

Guaranteed Analysis

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Crude Protein: 8%
Crude Fat: 6%
Crude Fiber: 1.5%
Moisture: 84.5%

Dry Matter Basis

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Protein: 51.61%
Fat: 38.71%
Fiber: 9.68%

Caloric Weight Basis

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Protein: 35.44%
Fat: 64.56%

Pros:

  • Inhibits excessive thyroid hormone production
  • Cats tend to like the taste of the food
  • A healthier alternative to the y/d dry food
  • A good last resort for cats who can’t undergo other treatments

Cons:

  • Low protein content doesn’t help to maintain muscle mass
  • Excessive carbohydrate content
  • Only effective if the patient doesn’t eat anything else

#2 Best Non-Prescription Pick: Smalls Fresh Bird Cat Food

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First 5 Ingredients: Chicken Thigh, Chicken Breast, Chicken Liver, Green Beans, Peas

Like most of the recipes on this list, Smalls fresh cat food doesn’t treat hyperthyroidism, but it does ensure that your hyperthyroid cat stays well-nourished during treatment and beyond.

Smalls cat food is human grade, fresh, lightly cooked cat food offered through a subscription service. While it’s not the most calorie-dense product, Smalls food is rich in highly-digestible animal protein to support healthy muscle mass and digestion.

Fresh chicken is the food’s primary ingredient, gently cooked to preserve its nutritional value. Also included in this recipe are green beans, peas, kale, and vegetable oil. The overall carbohydrate content is under 5%.

The food is free of fillers, artificial colors, flavors, or preservatives. In addition, you will not find any grains or ingredients like guar gum and xanthan gum on the ingredient list.

Ingredients:

Chicken Thigh, Chicken Breast, Chicken Liver, Green Beans, Peas, Water sufficient for processing, Chicken Heart, Kale, Vegetable Oil, Calcium Carbonate, Dicalcium Phosphate, Choline Bitartrate, Salt, Taurine, Magnesium Gluconate, Potassium Chloride, Zinc Gluconate, Ascorbic Acid, Copper Gluconate, Vitamin E Supplement, Manganese Gluconate, Ferrous Gluconate, Niacin, Thiamine Hydrochloride, Vitamin A, Calcium Pantothenate, Riboflavin, Pyridoxine Hydrochloride, Vitamin D3 Supplement, Folic Acid, Selenium, Dried Kelp, Biotin, Vitamin B12

Guaranteed Analysis

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Crude Protein: 17%
Crude Fat: 7.5%
Crude Fiber: 0.5%
Moisture: 73%
Ash: 2%

Dry Matter Basis

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Protein: 62.96%
Fat: 27.78%
Fiber: 1.85%

Caloric Weight Basis

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Protein: 48.28%
Fat: 51.72%

Pros

  • Shipped to your door with custom meal plans
  • Single source of high-quality animal protein
  • Low in carbohydrate content
  • Made from 100% human-grade, ethically sourced ingredients

Cons

  • Pricey when compared to store bought cat food
  • Smalls has a reputation for poor customer service

#3 Best Dry: Hill’s Prescription Diet y/d Thyroid Care Original Dry Cat Food

Hills Prescription Diet y-d Thyroid Care Original Dry Cat Food

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First 5 Ingredients: Corn Gluten Meal, Pork Fat, Whole Grain Corn, Soybean Mill Run, Egg Product

While the wet version of Hill’s y/d is nutritionally preferable, this kibble has all the same hyperthyroidism-appropriate qualities and is equally able to control your cat’s symptoms. In contrast to the wet recipe, it receives marginally better reviews and is—naturally—a more appealing choice for kibble enthusiasts.

The recipe is clinically proven to improve thyroid health in three weeks when it’s the only food a cat eats. In addition to restricted iodine for hyperthyroidism control, the food is formulated with S+OXSHIELD, which Hill’s says can help to prevent urinary crystals.

To address the kidney issues so common among senior cats, the food is relatively low in phosphorus and sodium. It’s rich in omega-3 fatty acids for inflammation relief.

Ingredients:

Corn Gluten Meal, Pork Fat, Whole Grain Corn, Soybean Mill Run, Egg Product, Chicken Liver Flavor, L-Lysine, Potassium Citrate, Lactic Acid, Dicalcium Phosphate, Fish Oil, Choline Chloride, Calcium Carbonate, Calcium Sulfate, DL-Methionine, Taurine, L-Tryptophan, Brewers Dried Yeast, vitamins (Vitamin E Supplement, L-Ascorbyl-2-Polyphosphate (source of Vitamin C), Niacin Supplement, Thiamine Mononitrate, Calcium Pantothenate, Vitamin A Supplement, Riboflavin Supplement, Vitamin B12 Supplement, Pyridoxine Hydrochloride, Folic Acid, Biotin, Vitamin D3 Supplement), minerals (Ferrous Sulfate, Zinc Oxide, Copper Sulfate, Manganese Sulfate), L-Carnitine, Mixed Tocopherols for freshness, Natural Flavors, Beta-Carotene

Guaranteed Analysis

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Crude Protein: 30%
Crude Fat: 20%
Crude Fiber: 3.5%
Moisture: 46.5%

Dry Matter Basis

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Protein: 56.07%
Fat: 37.38%
Fiber: 6.54%

Caloric Weight Basis

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Protein: 38.18%
Fat: 61.82%

Pros:

  • Can help control hyperthyroidism symptoms
  • Cats like the way this food tastes

Cons:

  • Doesn’t contain any meat
  • High carbohydrate content
  • Far from a species-appropriate food
  • Moisture-depleted dry cat food may contribute to chronic dehydration and poor health

#4 Best For Sensitive Stomach: Instinct by Nature’s Variety Original Grain-Free Real Lamb Recipe Canned Cat Food Review

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First 5 Ingredients: Lamb, Lamb Broth, Turkey, Turkey Liver, Ground Flaxseed

Ninety-five percent of this recipe is composed of lamb, turkey, and turkey liver. These are all sources of species-appropriate protein, which will help to support healthy muscle mass and prevent sarcopenia of aging (decline of muscle mass with age).

That said, this isn’t the most meat-dense food on this list. The recipe includes ground flaxseed, montmorillonite clay, peas, and carrots, none of which are ideal for cats. These inclusions bring the carbohydrate content to around 3% on a dry matter basis.

The company says that while they use a BPA lining in their large cans, their 5.5oz cans are BPA-free.

Ingredients:

Lamb, Lamb Broth, Turkey, Turkey Liver, Ground Flaxseed, Montmorillonite Clay, Eggs, Peas, Carrots, Potassium Chloride, Salt, Minerals (Iron Proteinate, Zinc Proteinate, Copper Proteinate, Manganese Proteinate, Sodium Selenite, Potassium Iodide), Choline Chloride, Vitamins (Vitamin E Supplement, Thiamine Mononitrate, Niacin Supplement, d-Calcium Pantothenate, Pyridoxine Hydrochloride, Riboflavin Supplement, Vitamin A Supplement, Biotin, Vitamin D3 Supplement, Vitamin B12 Supplement, Folic Acid), Taurine, L-Ascorbyl-2-Polyphosphate, Menhaden Fish Oil (preserved with Mixed Tocopherols), Artichokes, Cranberries, Pumpkin, Tomato, Blueberries, Broccoli, Cabbage, Kale, Parsley

Guaranteed Analysis

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Crude Protein: 10%
Crude Fat: 9%
Crude Fiber: 3%
Moisture: 78%

Dry Matter Basis

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Protein: 45.45%
Fat: 40.91%
Fiber: 13.64%

Caloric Weight Basis

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Protein: 31.39%
Fat: 68.61%

Pros:

  • High in moisture
  • Rich in biologically appropriate animal protein
  • Low in carbohydrates
  • Free from chemical preservatives, artificial ingredients, and animal byproducts
  • Soy-free

Cons:

  • Contains some fruit and vegetable ingredients

#5 Budget Pick: Wellness Complete Health Pate Chicken Entreé

Wellness Complete Health Pate Chicken Entreé

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First 5 Ingredients:  Chicken, Chicken Liver, Turkey, Chicken Broth, Carrots

Caring for a cat with hyperthyroidism gets expensive quickly. If you want to feed your cat well while saving enough money to pay for radioiodine treatment, medication, and vet visits, consider this food from Wellness Complete Health.

It’s not a prescription food and it won’t cure your cat’s hyperthyroidism, but it has all the nutrition to keep your cat feeling his best before and after treatment.

The food is primarily made from muscle-supporting animal protein sources like chicken, chicken liver, and turkey. It doesn’t contain any of our hyperthyroidism no-gos, meaning that it’s free of soy, fish, and high-iodine additives.

Regardless of size, all Wellness cat food cans and cups are BPA-free.

Ingredients:

Chicken, Chicken Liver, Turkey, Chicken Broth, Carrots, Natural Chicken Flavor, Sweet Potatoes, Squash, Zucchini, Cranberries, Blueberries, Guar Gum, Dicalcium Phosphate, Carrageenan, Ground Flaxseed, Potassium Chloride, Calcium Carbonate, Taurine, Iron Proteinate (a source of Chelated Iron), Beta-Carotene, Zinc Proteinate (a source of Chelated Zinc), Vitamin E Supplement, Choline Chloride, Cobalt Proteinate (a source of Chelated Cobalt), Thiamine Mononitrate, Copper Proteinate (a source of Chelated Copper), Folic Acid, Manganese Proteinate (a source of Chelated Manganese), Niacin, d-Calcium Pantothenate, Sodium Selenite, Vitamin D-3 Supplement, Pyridoxine Hydrochloride, Riboflavin Supplement, Vitamin A Supplement, Vitamin B-12 Supplement, Potassium Iodide, Biotin.This is a naturally preserved product.

Guaranteed Analysis

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Crude Protein: 10.5%
Crude Fat: 7%
Crude Fiber: 1%
Moisture: 78%

Dry Matter Basis

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Protein: 47.73%
Fat: 31.82%
Fiber: 4.55%
Carbs: 15.91%

Caloric Weight Basis

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Protein: 33.87%
Fat: 54.84%
Carbs: 11.29%

Pros:

  • One of the best values on the market
  • Doesn’t contain soy or other ingredients that might worsen thyroid function
  • Rich in nourishing animal protein
  • Low in carbohydrate matter
  • Packed in BPA-free cans

Cons:

  • Uses thickeners heavily
  • Contains carrots and several other plant ingredients

#6 Best For Seniors: Feline Natural Chicken & Venison Feast Cat Food

Feline Natural Chicken & Venison Feast Canned Cat Food

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First 5 Ingredients: Chicken, Chicken Heart, Venison Kidney, Venison Liver, Venison Blood

In an article on hyperthyroidism in cats, Pete Wedderburn, DVM, mentions the startling results of a recent study. When the blood samples of cats over the age of 10 were submitted for testing, 21% of the cats had elevated levels of thyroid hormones. With that many seniors experiencing some degree of hyperthyroidism, it’s worth finding food that addresses both thyroid function and senior health.

While this food from Feline Natural doesn’t treat hyperthyroidism, it can keep your senior cat healthy and strong without making hyperthyroidism worse.

It’s a readily-digestible food that features protein-rich animal ingredients like muscle meat, organs, and blood. In addition to these muscle-building ingredients, the food is rich in omega-3 fatty acids for inflammation relief and skin and coat health. Note that the food contains green-lipped mussels, which are ocean creatures high in iodine.

You may want to rotate this food with another seafood-free formula to keep iodine intake minimal.

Ingredients:

Chicken, Chicken Heart, Venison Kidney, Venison Liver, Venison Blood, Flaxseed Flakes, New Zealand Green Mussel, Dried Kelp, Taurine, Vitamin E Supplement, Magnesium Oxide, Zinc Proteinate, Copper Proteinate, Manganese Proteinate, Thiamine Mononitrate, Vitamin D3 Supplement, Folic Acid. Water added for processing.

Guaranteed Analysis

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Crude Protein: 9%
Crude Fat: 5%
Crude Fiber: 0.2%
Moisture: 82.5%

Dry Matter Basis

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Protein: 51.43%
Fat: 28.57%
Fiber: 1.14%
Carbs: 18.86%

Caloric Weight Basis

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Protein: 36.82%
Fat: 49.68%
Carbs: 13.5%

Pros:

  • Addresses multiple conditions common among senior cats
  • Rich in highly-digestible animal protein for sustained muscle mass
  • Low carbohydrate content is ideal for insulin-resistant cats
  • Doesn’t contain any thickening gums that might harm your cat

Cons:

  • Contains green-lipped mussel, which is high in iodine
  • One of the most expensive cat foods on the market
small mallory photo

About Mallory Crusta

Mallory is the Head of Content at All About Cats. Having produced and managed multimedia content across several pet-related domains, Mallory is dedicated to ensuring that the information on All About Cats is accurate, clear, and engaging. When she’s not reviewing pet products or editing content, Mallory enjoys skiing, hiking, and trying out new recipes in the kitchen. She has two cats, Wessie and Forest.

25 thoughts on “Best Cat Food For Hyperthyroidism

  1. Joe C

    Appreciate this article so much! Thanks!

    Would love if you can email me to chat, I have some questions after reading this.

    Reply
  2. David McCormick

    Great article. I have a question. We have a 17 year old cat with hyperthyroidism, and he has been having Hills Y/D for 2 years. It has improved his T4 count, but he is steadily loosing weight over time – possible due to age. Are you aware of any recommend suppliments we could give him along with the Y/D that may help increase his weight?

    Reply
    1. small mallory photoMallory Crusta Post author

      Hello David,

      Thanks for commenting.

      I contacted Hill’s and asked them about your situation and, unfortunately, wasn’t able to get much help there. As you know, it’s recommended that you feed the y/d diet as your cat’s only food source. Given that the diet relies on keeping iodine intake extremely low, most supplements seem to be out of the question.

      All in all, it’s probably a good time to see a vet. They can help you to determine exactly what is causing your cat’s weight loss and which type of diet will best address those underlying issues. While you’re with a vet, I’d also consider asking about vitamin B12 shots. These can help to increase your cat’s appetite and give him an overall health boost without increasing his iodine intake.

      I hope you get more answers soon and are able to find a diet or supplements that fit your cat’s needs.

      Best,

      Mallory

      Reply
  3. Cat

    I have hyPOthyroidism. I take a prescription called “Nature-Throid.” What is the main ingredient? LIVER!!! Apparently this helps my under-active thyroid.

    Although I am not a cat, it would seem that for hypERthyroidism, liver should be contraindicated! Yet the Hill’s Prescription food you suggest has its SECOND ingredient as liver. AND the FIRST ingredient is WATER. For pity’s sake, I can put water in their food. I don’t need to be paying though the nose for food with water as it’s most prominent ingredient!

    Seriously, it is like its all about money for the pet food companies, and not about the animals themselves.

    Reply
  4. Laura

    I started my cat on medicine for hyperthyroidism today. How long does it usually take to start reducing symptoms? Also my cat seems to always be hungry but when I put food down he hardly touches it. Is that ever a symptom of hyperthyroidism?

    Reply
  5. Demi

    Nature’s Variety Original Grain-Free Real Lamb Recipe Canned Cat Food contains salt, should I worry about it?

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi there. Many cat foods do contain salt and appropriate iodine levels are not well-established, so it’s very hard to say whether or not the lamb recipe from Nature’s Variety Instinct is an acceptable choice for cats with hyperthyroidism. This is an issue best discussed with a veterinarian.

      Reply
  6. Marita Brake

    My cat is hyperthyroid. He has been eating the y/d formula for abut 6 months but now has had it. Just won’t eat it. In an effort to get him to eat something, anything I tried wet Rachel Ray cat food. He gobbled it down. Now I am stuck between something which he will actually eat (but has possible cancer causing agents and the food he won’t eat that is good for him.
    Wondering what to do He is under a vet’s care, but at this point, I know more than the vet.

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Marita, apologies for the late reply! Have you been advised against other treatment routes? Hills y/d will not work if fed along with another diet, but at this time, it sounds like getting him to eat something supercedes the need to give him this therapeutic diet. I would consult with your vet on the alternatives like radiation or medication.

      Reply
  7. Sammie Ferguson

    vet just told me the options diet, med, radio?// something and surgery. surgery being best option we just don’t have that kind of money we are up in early 70’s we know all will be costly but will surgery leave her a healthy life no more problems or will she end up in pain and he said there is a small chance the other one ma become enlarged and have to do it again. My question she is a senior and I do have 4 other cats I would be willing to buy the special food and feed it to all of them to keep her from getting any regular food but is there any thing I can fix for her in my kitchen with out salt and stuff lets say chicken beef or lamb not so sure about pork but no fish that would help her to gain some of her muscle mass she has lost quit a bit. I’m torn my husband would agree with surgery if her life will be a good one if not he says no. any suggestions on the home food in addition to the y-d food please she is my baby. They are the babies of the last strays we took in we fixed them all and eventually the adults left and found new homes. range in age Toppy the one that is in question and Jill 10yrs, Winky 9yrs and Ida Mae 8yrs except Raven my sons cat 19yrs any pointers you can give to avoid the alternative.

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Sammie, thank you for commenting. You’ve brought up some good questions. It is true that surgery or administering radioactive iodine therapy (which has a 95%+ success rate) are preferable to long-term medication or reliance on the y/d diet. If you can afford the injection, I would recommend this as your number one option. As for homemade food, that’s very tricky. I imagine that it should be possible, but I don’t have any specific suggestions. Please reach out to the All About Cats community with this question, as we have a team of vets at the ready to give you some insights.

      Reply
    2. Jess

      Hi Sammie,
      I’m so sorry to hear about your cat. I’m not a vet, but do have some experience in what you are going through. Human table salt would be the biggest concern for Hyper-t pets, as our table salt is infused with iodine. Not that high-sodium diets are good for cats, but the salt in their food is usually not iodine-salt. I have a pair of adopted cats, they are currently 15 years old. My boy cat was diagnosed with Hyper-T around 5 years ago. After an abundance of research, I wanted to do the radioactive iodine-131 (131I) therapy & found a pet clinic that did it in St. Louis, MO & that time the treatment cost around $700. However, your cat’s heart and kidneys need to be in good shape, as Hyper-T masks kidney decline/disease you may not know how his kidneys are until you have his thyroid levels back in range (through meds). So, our vet put him on anti-thyroid meds. After 30 days, we took him in for blood work and while his Thyroid levels were back in the normal range, she mentioned that she did see *some* decline in renal function. As he was 12, she suggested we stay on the meds, but could certainly ask the 131I clinic if they thought he was a good candidate. After all the distress this had caused, I elected to remain on the meds. I will say now, I highly regret that decision. The radioactive iodine treatment is typically 1 shot of radioactive iodine which goes into the system, directly targets the thyroid tumor tissue and it, along with the treatment is excreted. Your cat would have to stay in the clinic until they are no longer secreting the radioactive iodine, which could take anywhere from a few days to a week. If done in 1 does (95% success rate at 1 dose), they should no longer be hyperthyroid. Leaving him on meds means I have to pill him every 12 hours, and he needs regular blood tests (every 3-6 months) as the thyroid tumor continues to grow, so the dosage goes up over time. I won’t get too detailed here as any treatment is better than none, but the medicine comes with it’s own set of problems. If you vet is suggesting surgery, your cat likely has a healthy heart & kidneys, and is likely healthy enough to go through the iodine treatment. It’s non-invasive as it’s just a shot, and after a little bit of time in the kennel to excrete the radioactivity, they are usually 100% cured. Anyway you go, I highly recommend removing fish from his diet completely, as current science- while not identified as the cause for sure- indicates a likelihood that the high metal levels in fish could be the cause. I can say, with no doubt, fish treats absolutely throw him out if whack. He won’t even touch food that has fish in it now, which was his favorite (from my dinner plate that is). Also, my girl cat (his 15 yr. old sister) never cared for (my) fish, but otherwise had the exact same diet & environment, but she does not have hyper-t. A diet that is high, animal-based protein is NEEDED for seniors, especially so with Hyper-T, as it’s basically like having your engine revving at 100mph all day long. This is a fatal disease without treatment, so please make sure your choice of care is something you & Toppy can both manage. All treatment options have pro’s and cons, so please make sure your vet is willing to discuss the full pro’s & con’s of each treatment and is weighing them against your cats overall health. Best of luck!

      Reply
  8. Valerie Phillips

    Hi, I recently started feeding my hyperthyroid cat Smalls cat food. Human grade, few ingredients. It doesn’t list iodine as an ingredient… are there other names for iodine? I don’t think they carry any fish varieties. It isn’t in cans and must be kept refrigerated or frozen.have you evaluated this brand?

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Valerie! That’s an excellent question. Smalls cat food doesn’t list iodine on their nutrient labels, but this mineral is found in many foods, including meats (not just fish). Unfortunately, I don’t have those iodine values on hand, but you can contact Smalls for more information: meow@smalls.com
      If you’d like to learn more about Smalls, you can read our complete review of the brand here.

      Reply
  9. ED DUBIAC

    I have 5 cats all with health issues. Bella my 13 yr. old was just diagnosed with hyper t & is being treated with the transdermal med. She is skin & bones. The vet has not put her on a special diet yet but my question is can all of my cats eat the Hills hyper t dry food or will it hurt them? All of my cats share a community dry food bowl. Any advice would be appreciated.

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi Ed, thanks for commenting! We don’t really know how an iodine-restricted diet will affect cats who don’t have hyperthyroidism. If you choose this diet, I would recommend restricting it to Bella only. That’s going to be a challenging transition from the community bowl—a couple of microchip feeders may be the best solution to ensure that the other cats don’t eat Bella’s food and vice versa. Wishing you all the best.

      Reply
  10. Karen Milnor

    I have a 17 year old Norwegian Forest cat who just recently developed hyperthyroidism. I read the following article and thought I’d share it because some of the dietary views differ from your recommended food list while other views are the same. My opinion is that mimicking as closely as possible a cats diet in the wild, taking into account what their bodies were meant to ingest, is the best dietary route. Every dry food will fall short of those requirements including Hills. I hope people find this helpful. I know people get very defensive about their pets and how they care for them. This is info from experts in feline veterinary endocrinology. https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.felinehtc.com/documents/Feeding-Cats-With-Hyperthyroidism-Newsletter-July-2015.pdf&ved=2ahUKEwjhhuCrsc73AhXKATQIHXl0AXsQFnoECC4QAQ&usg=AOvVaw0sH_dp2YhKIiH1IkzU4v3j

    Reply
  11. SB

    Below your words regarding Canned YD.
    Because it’s restrictive, not species-appropriate, and isn’t a real cure, think of this diet as a temporary measure or as a last resort for cats who can’t undergo surgery or receive radioiodine.
    ME:
    WOW are you more interested in pushing a brand of cat food than caring about felines & the people who love them?
    Have you ever had a cat that’s had radioactive iodine ?
    Are you aware of the many complications and health issues and life-threatening possibilities that come from radioactive iodine ?
    Are you aware of the negative side effects that are toxic with the one pharmaceutical drug that’s available to cats for hyperthyroidism ?
    You are not aware and I will not educate you here but do not mislead people and put the people’s cats at risk .
    Currently why did canned is the safest of the three Alternatives I’ve been around the block and all directions and have definitely looked at the science.
    YOUR NEXT COMMENT:
    It starves the thyroid of fuel, but it doesn’t slow down the progression of a thyroid tumor. The tumor will continue to grow and potentially change into a carcinoma.
    ME: WOW again. To say I’m shocked as an understatement. You’re telling everyone that everyone’s cat is going to end up getting a carcinoma tumor if they eat yd cat food. SHAME ON YOU!
    You made a lot of good points and then I got to those two and then the next brand underneath the yd canned has kelp in it do you know kelp is extremely high in iodine and you are recommending that people treat their hyperthyroid cats with that dry cat food.
    Kelp is one of the highest iodine Foods there is a cat eats that they’re going to get hyperthyroid again and that’s what’s dangerous do you know what hyperthyroidism does to the body?
    Myself I have a thyroid disorder and I’ve had several cats with hyperthyroidism and I know what I’m talking about and I’m not even going to read the rest of your article it’s nonsense I doubt you’ll even express what I’m saying here but you need to go back to the drawing board because you’re putting cats at rest

    Reply
    1. small mallory photoMallory Crusta Post author

      Hi there, thank you for the thoughtful comment. I’m lining this article up for review by a veterinarian to ensure that all of the statements made here are accurate and in line with the latest veterinary recommendations—it does seem that it’s in need of an update.

      Reply
  12. PAPADSL

    I have had cats for about 27 years. Like many of you readers, I historically made the incorrect assumption that if petfood was good enough to be stocked on grocery store shelves that it was safe for my pets. A few years ago I started buying what is supposed to be premium cat food, with the same assumption–that if it was on the shelves, it was safe. and I was paying a hefty price for the premium cat food, so it had to be beter for my cats, right? WRONG!
    Withi the last year and a half, I have had several cats suffer and/or die of hyperthyroidism. It was some new trend. The vets at my vet office, both living fewer years than I have a had cats, said it was just common with old age. They were speaking with maybe 5 or 10 years of vet experience, but my 27 years of cat ownership was saying NO. This is a new trend. But WHY? Did some research, and found a whole bunch of adverse data regarding a common pet food ingredient called sodium selenite. Guess when the FDA and te AAFCO started recommending that this ingredient be added to pet food? It was sometime in 2016. Folks–read up on SODIUM SELENITE. IT IS TOXIC. It is in MANY cat foods. Additionally, did you know, that there is a maximum allowable amount of sodium selenite for humans, and a maximum allowable amount of sodium selenite for dogs. BUT NOT A MAXIMUM ALLOWABLE AMOUNT OF SODIUM SELENITE FOR CATS. *****WHY NOT?????!!!
    Been buying First Mate canned chicken an turkey, but my cats get sick of it, even if I mix in a little Fussy Cat or other for a different flavor. And the reviews here say that it is just ok for the species appropriate rating due to the pea starch carbs. So far I find it is the least evil solution. Other cat foods have much higher carbs, or a bunch of useless fillers, sodium selenite, or kelp–which another respondent here pointed out has IODINE in it, which is BAD FOR CATS WITH HYPERTHYROIDISM.
    GOOD LUCK AND GOOD HEATH TO YOU AND YOUR CATS.

    Reply
  13. Georgetta Williams

    My male cat has been diagnosed with hyperthyroidism. He is on methimazole. He is very picky about what he eats. He has had diarrhea for a month or so, very runny. He has a very hard time when he goes into liter box. He really strains. I have tried pumpkin. I need ideas on how to firm up his stool.

    Reply

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