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

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8.5-lb bag
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Hill's Prescription Diet y/d Thyroid Care is the safe, effective and easy way to manage thyroid health. Clinically proven nutrition to restore thyroid health in 3 weeks.

Key Benefits

  • Clinically proven to improve thyroid health in 3 weeks when fed as the sole source of nutrition
  • Decreases T4 hormone production while supporting kidney, heart and urinary health
  • Helps support a healthy body condition and a healthy immune system while also promoting a visible improvement in skin and coat
  • This recipe has limited iodine and controlled phosphorus and low sodium
  • Promotes desirable urine pH levels and is high in taurine, L-carnitine and omega 3 fatty acids

Special Note

Hill's Prescription Diets require a veterinary prescription. This product will not be shipped until a copy of a valid prescription authorization is faxed to 1-800-619-7973 or e-mailed to rx@chewy.com.

See all items by Hill's Prescription Diet

  • Item Number
  • Brand
    Hill's, Science Diet
  • Food Form
    Dry Food
  • Lifestage
  • Made in
    United States
  • Special Diet
    Prescription Food

Nutritional Info


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

Caloric Content

  1. 517 kcal/cup
Guaranteed Analysis
Crude Protein 30.0% min
Crude Fat 20.0% min
Crude Fiber 3.5% max
Phosphorus 0.45% min
Phosphorus 0.85% max
Sodium 0.3% max
Iodine 0.2% max
Taurine 0.15% min
Carnitine 200 ppm min

Feeding Instructions

Because iodine intake from other food sources -- treats, another cats food, etc. -- can compromise the effectiveness of low-iodine nutrition, its critical that you follow your veterinarians feeding instructions carefully and feed only y/d.Adjust feeding amounts as necessary to maintain optimal weight. If you are unsure, ask your veterinarian. For best results & safety practices: Gradually transition to your pets new food over a 7 day period. Exclusively feed the recommended Prescription Diet dry and/or canned food. Keep fresh water available at all times. Have your veterinarian monitor your pets condition.

Transition Instructions

A gradual transition to a new pet food is important to avoid digestive upset. To transition, mix your pet’s current food with the new food. Over 7 days, gradually decrease the amount of the current pet food while increasing the amount of new pet food. In some cases, your veterinarian may recommend no transition or a shorter transition time.

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Customer Reviews

104 reviews 104 Reviews 4.7 out of 5 Stars
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98% Recommend

98% of reviewersrecommend this product

4.7 / 5
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  • Good stuff

    By on

    My cat likes this food, had no problem switching form his previous food. So far it's managing the thyroid problem just fine, he's a healthy, soon to be fourteen year old with glossy fur and I'm grateful for this easy solution and grateful for chewy dot com for their amazing fast shipping.

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  • Very happy customer.

    By on

    I could not be more happier with the Science Diet Thyroid diet y/d and the wet can food y/d. They went to it right away, at least Allyson did, she was the one with the problem. Abby it took a little longer for her, she is on the dry and she gets a different wet food. But, I hope this will help in there recovery in the long run. I love your company, such great service ,speedy delivery. I am one happy camper. Thank you, Ms. Bonnie Sella

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  • High quality!!

    By on

    The Hill's Prescription Diet Y/D feline formula was received within 2 business days and was 1) a bigger bag than I could get locally, and 2) far cheaper when I signed up for auto shipments and was a 1st time customer!! I also ordered a Sergeant's fine tooth undercoat comb / brush combo tool, and love it too!

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  • It works

    By on

    my cat has hyperthyroidism. The blood test was REALLY really negative. We tried medicine but the med was affecting my cat's liver horribly. Stopped med and tried food. Cat thinks it okay...not loving it, but eating it. I am very happy, since the vet said thyroid irradiation would be next option to over $3K or so. He just needs to gain weight. I only ask Hills to work on better tasting food LOL.

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  • My cat gained over a pound! Love Chewy.com

    By on

    My nearly 16-year-old cat was losing weight and was down to 8.2 pounds, after being 12 or 13 throughout her life. Found out her thyroid was severely out of balance and vet recommended this food. She gained more than a pound in a month and is no longer racing around at night. And she loves it! Also, found this somewhat expensive food for $10 cheaper on Chewy.com and love that it is free shipping and we can have it shipped to our house on our schedule. Chewy's customer service is outstanding, received a kind note as soon as I ordered and her food arrived a day earlier than expected. Wish I would have found this site sooner!

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  • Rave reviews from my 2 cats!

    By on

    My 2 cats give this food rave reviews! My 10 year old cat with thyroid problems loves this dry food, easy for her to eat, too. My young 3 year old normal cat also loves to crunch these nuggets. Both dry and wet food have really helped my 10 year old to regain her normal weight quickly, plus receiving thyroid medicine. Love this product!! Great store, also!

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  • Great product, great service

    By on

    My senior cat was recently prescribed Hill's y/d for hyperthyroidism. I had concerns about introducing a new food, but I needn't have been. Both he and his brother (no health issues) love it. Great quality and delivered to my door in a day or two. Thanks Chewy!

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  • Too Soon To Tell

    By on

    Zoey has just started eating the special thyroid food. We will be able to tell if it is working when she goes in for her next bloodwork. Can't give it an honest rating yet.

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  • prescription diet

    By on

    Vet prescribed for a little old kitty who came in as a found stray, she would rather eat this dry then the canned version but its doctors orders to try this for 3 weeks and see if there is a difference

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  • Great Product and Service

    By on

    It has only been a few weeks but Baby Jade is already better! She seems to enjoy the product also.

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