Best Cat Food for Hyperthyroidism 2024 Cats.com (2024)

Kirsten McCarthy / Cats.com

Best Prescription

Best Dry Prescription

Best Freeze-Dried

Best For Picky Eaters

Best Noval Protein

Best for Pate Lovers

Best for Weight Gain

#1 Best Prescription: Hill’s Prescription Diet y/d Thyroid Care with Chicken Wet Cat Food

• Made In: United States
• Guaranteed Protein (Dry Matter): 31.82%
• Iodine (Dry Matter): 0.1 ppm
• Price:$0.63 per oz

Formulated specifically for cats with hyperthyroidism, this prescription cat food contains 0.1ppm of iodine. It’s been clinically shown to decrease thyroid hormone (T4) production after 3 weeks as a staple diet. It may also help reduce your cat’s risk of developing struvite and calcium oxalate crystals.

Hill’s also offers a dry food formula for thyroid care, but we recommend a high-moisture diet whenever possible. This canned cat food is rich in moisture and contains about 32% protein and 25% fat, both measured as dry matter.

While this is the only prescription cat food proven effective for cats with hyperthyroidism, it isn’t nutritionally ideal. The recipe contains pork liver and chicken muscle meat, but it also contains pork by-products, corn flour, and artificial chicken liver flavor.

Overall, the carbohydrate content of this recipe is much higher than we’d like and the high fiber content (over 11% as dry matter) could contribute to digestive issues in cats who aren’t used to a high-fiber diet. The food also contains guar gum, a binder and thickener that may cause loose stools in some cats.

NOTE: Customers should be aware that Hill’s changed the formula and package design for this product in Spring 2023. As of May 2023, Chewy was still selling the original formula but the new formula is available on Amazon.

A Chewy customer representative confirmed that they will be switching to the new recipe when their current stock runs out. If you shop on Chewy prior to the changeover, keep some extra food on hand so you can use it to slowly transition your cat onto the new formula when it becomes necessary.

What We Liked:

• Formulated to reduce thyroid hormone production
• Relies primarily on animal protein and fat
• Rich in moisture to support your cat’s hydration

What We Didn’t Like:

• High in carbohydrates
• Contains corn ingredients and artificial flavor
• Only available by prescription

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

• Made In: United States
• Guaranteed Protein (Dry Matter): 35.4%
• Iodine (Dry Matter): 0.2 ppm
• Price:$9.41 per lb

Hill’s Prescription Diet y/d Thyroid Care dry cat food takes a multi-faceted approach to controlling hyperthyroidism in cats. First, omega-3 fatty acids control phosphorus levels and reduce sodium. This cat food also limits iodine, which contributes to hyperthyroidism. As a result, it decreases T4 hormone production, promoting a healthy thyroid in as little as three weeks (when it’s the only source of nutrition).

This prescription diet also supports overall health, addressing issues like urinary tract infections, which can be common in cats with hyperthyroidism.

Trying this prescription food first can be an easy way to manage your cat’s hyperthyroidism without turning to medicines or more aggressive treatments. And, according to reviews, it works — as long as your cat isn’t a picky eater. In some cases, this food restores normal thyroid function, eliminating the need for pilling or surgery.

What We Liked:

• High in omega-3 fatty acids
• Developed by over 220 experts in the food industry
• Formulated to reduce T4 hormone levels
• The resealable bag makes it easy to store

What We Didn’t Like:

• Per reviewer feedback, some cats don’t like the food
• Rather expensive

#3 Best Freeze-Dried: Vital Essentials Freeze-Dried Raw Pork Mini Nibs Entree Cat Food

• Made In: United States
• Guaranteed Protein (Dry Matter): 48.9%
• Iodine (Dry Matter): 0.9 mg/kg
• Price:$1.96 per oz

Raw cat food must be frozen or refrigerated to stay fresh but freeze-dried raw food offers a shelf-stable alternative. Freeze-dried raw food has the moisture removed, so it’s best to reconstitute each portion before feeding it to your cat to support adequate hydration.

This Vital Essentials formula features pork as a single source of animal protein, inclusive of muscle meat and organs. Herring oil is a species-appropriate source of fat, particularly omega-3 fatty acids. Measured as dry matter, the protein content of this food is nearly 49% and the fat content is almost 34%.

According to a typical analysis received from Vital Essentials, this formula contains the lowest iodine levels of their cat food recipes. It tested at 0.9mg/kg of iodine.

Overall, this is a high-protein, high-fat freeze-dried cat food with low carbohydrate content. It should be rehydrated to provide for your cat’s moisture needs but it’s a single-protein recipe that should be highly digestible for most cats.

What We Liked:

• Made with a single source of animal protein
• Herring oil provides plenty of animal-sourced omega 3s
• Very low carbohydrate content
• Highly digestible recipe made with a short list of ingredients

What We Didn’t Like:

• Low moisture, should be rehydrated before feeding
• Expensive, nearly $2 per ounce

#4 Best Subscription: Smalls Ground Other Bird Fresh Cat Food

• Made In: United States
• Guaranteed Protein (Dry Matter): 51.79%
• Iodine (Dry Matter): 5.4 mg/kg
• Price: $0.80 per oz.

Fresh cat food poses some of the same challenges as raw food in terms of storage but if you have the freezer space, Smalls offers the convenience of regular deliveries. This subscription service enables you to create a custom meal plan for your cat with several proteins and textures to choose from.

According to a customer service representative, Smalls fresh turkey recipes test at 1.7 mg/kg iodine as fed, or about 5.4 mg/kg as dry matter. As fed, their beef recipe tests at 1.5 mg/kg, their chicken recipes at 2.1 mg/kg, and their single fish recipe at 1.3 mg/kg.

The Ground Other Bird formula features finely diced turkey thigh and turkey liver. Measured as dry matter, this fresh food formula contains over 51% protein and 35% fat. The dry matter carbohydrate content is very low and the recipe is highly digestible for most cats.

Overall, this is a very high-protein, high-fat formula with plenty of moisture to support your cat’s hydration. Smalls uses ingredients fit for human consumption and their foods are flash-frozen to keep them fresh during shipping.

What We Liked:

• Made with a single source of animal protein
• High in protein with low carbohydrate content
• Rich source of hydrating moisture

What We Didn’t Like:

• Only available as a subscription plan
• No phone support (text and email only)

#5 Best Noval Protein: Savage Cat Food Rabbit & Lamb Frozen Cat Food

• Made In: United States
• Guaranteed Protein (Dry Matter): 53.3%
• Iodine (Dry Matter): 0.33 mg/kg
• Price: $1.25 per oz

Not only is a raw food diet one of the most species-appropriate choices for cats, but it also tends to be lower in iodine than the typical commercial cat food. Savage Cat Food offers three recipes for cats – duck, chicken, and rabbit & lamb. According to a customer service representative, all three formulas contain less than 1.0mg/kg of iodine measured as dry matter.

This rabbit & lamb formula from Savage Cat Food features whole rabbit ground with bone. It also contains lamb organs, egg yolks, and various bovine and porcine tissues. Savage uses rabbit sourced from sustainable farms in the United States and humanely raised lamb from Superior Farms in Dixon, CA.

When measured as dry matter, this recipe contains over 53% protein and about 30% fat. The dry matter carbohydrate content of the food is under 10% and the iodine is measured at 0.33mg/kg.

Overall, this is a very species-appropriate choice for cats and the high protein, low carbohydrate, and low iodine content may benefit cats with hyperthyroidism.

What We Liked:

• Species-appropriate blend of muscle meat, organs, and bone
• Rich in moisture to support your cat’s hydration
• Very low carbohydrate content, under 10%
• Free from high-iodine ingredients like fish and seaweed

What We Didn’t Like:

• Expensive to feed
• May not be appropriate for cats with beef or pork allergies

#6 Best For Pate Lovers: RAWZ 96% Chicken & Chicken Liver Pate Cat Food

• Made In: Thailand
• Guaranteed Protein (Dry Matter): 50%
• Iodine (Dry Matter): 2.23 mg/kg
• Price:$0.72 per oz

If your cat prefers pate-style foods, this chicken and chicken liver recipe from RAWZ is a species-appropriate choice. It’s made with 96% chicken muscle meat and chicken liver, making it a single-protein recipe. It’s also moisture-rich to support your cat’s hydration and improve digestibility.

This is a high-protein wet food, formulated to contain 50% protein and nearly 32%, measured as dry matter. According to a typical analysis posted on the RAWZ website, however, the food tests even higher at 12.2% protein and 9% fat, as fed – about 55% dry matter protein and 41% dry matter fat.

According to the same nutrient analysis, this recipe contains about 2.23mg/kg iodine. The food contains fenugreek seed as a binder which negates the need for gums and seaweed-based ingredients like agar-agar and carrageenan.

Overall, this is a very high-protein, high-fat cat food that provides plenty of hydrating moisture. It’s a simple, very digestible recipe with low carbohydrate content.

What We Liked:

• Features a blend of chicken muscle meat and chicken liver
• Highly digestible, short list of ingredients
• Rich in hydrating moisture for your cat
• Free from gums and seaweed-based thickeners

What We Didn’t Like:

• Expensive to feed

#7 Best For Weight Gain: Wellness CORE 95% Chicken Grain-Free Canned Cat Food

• Made In: United States
• Guaranteed Protein (Dry Matter): 47.73%
• Iodine (Dry Matter): 2.81 mg/kg
• Price:$0.61 per oz

Hyperthyroidism can prevent your cat from metabolizing energy as well as they should which can lead to weight loss. The caloric density of this Wellness CORE recipe could be a good fit for cats who need to regain muscle mass during or after treatment for hyperthyroidism.

This formula features chicken muscle meat as the main ingredient, lending a dry matter protein content of nearly 48%. The food contains over 36% dry matter fat and has about 36 calories per ounce.

According to a typical analysis, this formula contains about 2.81mg/kg of iodine, measured as dry matter. Other Wellness CORE formulas tested lower – like Wellness CORE Signature Selects Chunky Chicken & Turkey – but these recipes were higher in carbohydrate.

This Wellness CORE 95% Chicken recipe contains under 10% dry matter carbohydrate, according to the same typical analysis used to determine the iodine content.

What We Liked:

• Made with a single source of animal protein
• Contains nearly 50% protein, measured as dry matter
• Calorie-dense, may help underweight cats gain muscle mass
• Easily digestible recipe made with limited ingredients

What We Didn’t Like:

• Gum thickeners may cause loose stools in some cats