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

By Hill's Prescription Diet
Rated 4.4668 out of 5 stars
Veterinary Diet Item


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About This Item


  • See results in as little as three weeks when fed as the sole source of nutrition.
  • Thyroid Care works to decrease T4 hormone production while supporting your cat's kidney, heart and urinary health.
  • Helps support lean muscles and a strong immune system while also promoting a visible improvement in skin and coat.
  • Formulated with S+OXSHIELD to help reduce the risk of developing struvite and calcium oxalate crystals in urine.
  • Contains limited iodine, controlled phosphorus and reduced sodium levels.

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Nutritional Information

Feeding Instructions


Play Video: Learn More About Hill's Prescription Diet From Our Team of Experts
Learn More About Hill's Prescription Diet From Our Team of Experts

Frequently Bought Together

This Item – Hill's Prescription Diet y/d Thyroid Care Original Flavor Dry Cat Food, 8.5-lb bag
Rated 4.4668 out of 5 stars
$76.99Chewy Price

Spend $100, Get a $15 eGift Card

Hill's Prescription Diet y/d Thyroid Care with Chicken Wet Cat Food, 5.5-oz, case of 24
Rated 3.8714 out of 5 stars
$81.99Chewy Price

Spend $100, Get a $15 eGift Card

Ethical Pet Can Covers, 3 pack
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Hill's Prescription Diet y/d Thyroid Care for Cats

Groundbreaking Nutrition for Thyroid Health

Hill's breakthrough formula was designed to help felines with hyperthyroidism thrive. Cats with this disorder have an overactive thyroid gland—meaning it produces too much of the thyroid hormone—but limiting iodine in your cat's food can help regulate it. Prescription Diet y/d does that and more, all in a tasty kibble your cat will love. You may even see a difference in as little as three weeks.

Clinical Nutrition

With Hill's, it's not just high-quality ingredients that count. Their focus is on the proper balance of nutrients in every recipe. So, Hill's designed food to help pets with health conditions, providing the right nutrients to support their health. Hill's alliance with veterinarians puts them in a position to find a nutrition recommendation for your pet, no matter what health issue your pet is facing.

Formulated by Veterinarians

Hill's Prescription Diet started with a veterinarian's belief that some health issues could be managed through nutrition. What began as a theory has now been proven through extensive research by a team of over 220 vets, PhD nutritionists and food scientists. The results can be seen in Hill's Prescription Diet therapeutic pet foods.

Meeting the Highest Standards

Providing a food that delivers exactly what it says it does is Hill's number one priority. In fact, they perform over five million safety and quality checks every year. They've established relationships with trusted suppliers and will only accept ingredients that meet stringent standards.

The Taste Factor

You might know that Hill's Prescription Diet is good for your pet, but she's only concerned with the taste. Even though they place a heavy emphasis on nutrition, Hill's hasn't forgotten about palatability. Savory ingredients are combined to produce foods with enticing aromas, textures, and shapes that your pet can't resist.

How Hill's y/d Helps Manage Thyroid Health

Key Nutrients

  • Limited Iodine
  • High in omega-3 fatty acids
  • Controlled phosphorus and low sodium

Health Benefits

  • Decreased T4 production
  • Supports kidney, heart and urinary health
  • Promotes skin and coat health

About Hill's Prescription Diet

Hill's mission is to help enrich and lengthen the special relationships between people and their pet. Their Prescription Diet product line delivers clinically proven nutrition that supports common pet health concerns, from digestive and urinary health to aging and weight management.
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Questions & Answers

17 Customer Questions

I have 2 cats and only has a hyperthyroid. The vet meds have made him so sick that I wanted to try an alternative. Will this food be harmful if eaten by my cat who doesn't have hyperthyroidism but has asthma? They share a dry food bowl and feeding them independently would be a challenge. Thank you.
Answer by ChewyNov 15, 2018
Since this is a prescription food formulated to meet specific diet restrictions from known health issues, this food should not be fed to any other animal than the one prescribed due to the restriction of specific nutrients. Prescription diets can be detrimental to an otherwise healthy pet if that pet doesn't have the ailment for which the food is designed.

Is this food for an over-active or under-active thyroid problem (i.e. hyper- or hypo-thyroidism)?
Answer by ChewyApr 23, 2018
This formula is not designed for over-active or under-active thyroids specifically, instead it helps to promote the overall health of the thyroid. It contains limited iodine to decrease T4 hormone production. This product also supports kidney, heart and urinary health with controlled phosphorus, low sodium, and a desirable urine pH.

Is it safe to feed this to a hyperthyroid cat does take methimazole, but not always the full dose? She is also in very early renal failure. Are the phosphorus & sodium levels low enough to be beneficial?
Answer by ChewyNov 20, 2019
Due to your feline's underlying medical condition, we suggest speaking to your veterinarian to determine if this is the best option for your cat.

Does the 8.5 lb bag not have the S+OXSHIELD? when I hover over the 8.5 lb option, the S+OX logo disappears from the photo of the bag.
Answer by ChewySep 11, 2018
Both the 4 and 8 1/2 pound bags are formulated with the S+OXSHIELD to meet specific nutrient standards, shown to promote a urinary environment that helps reduce the risk for struvite and calcium oxalate crystals.

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Rated 4.4668 out of 5 stars
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372 Customer Reviews

Always consult a veterinarian about your pet’s health needs. Customer reviews should not be used as medical advice.
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