Royal Canin Hydrolyzed Protein vs. Hill’s Z/D

When your furry friend has dietary sensitivities, finding the right food is more than a necessity—it’s a priority. If you’re wading through the myriad of options, you may have come across Royal Canin Hydrolyzed Protein and Hill’s Prescription Diet z/d. Both are top contenders for managing food sensitivities and allergies in dogs, but which one is best for your pet?

Key Takeaways for Quick Readers:

  • Main Ingredient: Royal Canin uses hydrolyzed soy protein, whereas Hill’s z/d uses hydrolyzed chicken.
  • Purpose: Both are designed for dogs with food sensitivities or allergies.
  • Availability: Prescription only.
  • Packaging Options: Both offer dry and canned food versions.
  • Veterinary Recommendation: Consult your vet before switching to a specialized diet.

What Are Hydrolyzed Protein Diets?

Hydrolyzed protein diets are designed for dogs with allergies or intolerances to common food proteins. In these diets, the protein is broken down into smaller pieces, which are less likely to trigger an allergic reaction. This makes them an excellent choice for managing diet-related skin and gastrointestinal issues.

Royal Canin Hydrolyzed Protein

🐾 Main Features:

  • Protein Source: Hydrolyzed soy protein.
  • Designed For: Dogs with severe allergies or intolerances.
  • Benefits: Promotes skin health and aids in digestive problems.
  • Veterinary Approval: Required.

📊 Product Variants:

  • Adult HP Dry Dog Food
  • Small Dog HP Dry Food
  • Canine Hydrolyzed Protein Wet Dog Food

Hill’s Prescription Diet z/d

🐶 Main Features:

  • Protein Source: Hydrolyzed chicken.
  • Designed For: Dogs with food allergies and sensitivities.
  • Benefits: Highly digestible, improves skin and coat health.
  • Veterinary Approval: Required.

📊 Product Variants:

  • Original Skin/Food Sensitivities Dry
  • Skin/Food Sensitivities Small Bites Dry
  • Original Wet Food

Comparing the Two

FeatureRoyal Canin Hydrolyzed ProteinHill’s Prescription Diet z/d
Protein SourceHydrolyzed soy proteinHydrolyzed chicken
FormDry and wetDry and wet
Specific UseSevere allergies/intolerancesGeneral allergies/sensitivities
BenefitsAids digestion, promotes skin healthHighly digestible, improves skin and coat
AvailabilityPrescription onlyPrescription only
Packaging OptionsSmall and standard kibble, cansSmall bites, standard kibble, cans

Critical Insights and Tips

Consult Your Veterinarian

Before switching your dog’s diet, a thorough discussion with your veterinarian is crucial. They can help determine if a hydrolyzed protein diet is necessary and which brand might suit your dog’s specific health needs.

Transition Gradually

When introducing a new food, especially one as specific as a hydrolyzed protein diet, transition your dog slowly to avoid gastrointestinal upset. Mix the new food with the old in increasing amounts over a week.

Monitor Your Dog’s Response

Keep an eye on how your dog responds to their new diet. Improvements in skin condition or gastrointestinal symptoms can be a good sign, but any negative reactions should prompt a call to your vet.


Choosing between Royal Canin Hydrolyzed Protein and Hill’s Prescription Diet z/d depends on your dog’s specific health needs and reactions to different protein sources. Both are excellent choices designed to manage food allergies effectively, so your decision should be guided by professional veterinary advice and your pet’s individual health.

Interview with Dr. Emily Norton, Veterinary Nutrition Specialist

Q: Dr. Norton, could you explain why hydrolyzed protein diets are recommended for dogs with food allergies?

Dr. Norton: Absolutely! When dogs have food allergies, their immune systems mistakenly identify certain protein molecules as threats, leading to adverse reactions. Hydrolyzed protein diets contain proteins that have been broken down—chemically ‘sliced’ into smaller pieces that are typically too small for the immune system to recognize. This significantly reduces the risk of triggering an allergic response, making these diets particularly beneficial for managing and mitigating food allergy symptoms in dogs.

Q: What are the most common signs that a dog might benefit from a hydrolyzed protein diet?

Dr. Norton: Great question! The signs can vary, but typically, you might notice chronic gastrointestinal issues such as diarrhea, vomiting, and excessive flatulence. Skin problems are also a common indicator, like persistent itching, redness, or hair loss that doesn’t seem to resolve with typical treatments. If a dog exhibits these symptoms, it’s a cue that we might need to explore dietary changes, particularly if these symptoms persist despite other interventions.

Q: How do Royal Canin and Hill’s approach the formulation of their hydrolyzed protein diets differently?

Dr. Norton: Royal Canin and Hill’s both strive to meet the needs of sensitive pets, but their approach to hydrolyzed proteins differs subtly yet significantly. Royal Canin primarily uses hydrolyzed soy protein, which is an excellent choice for dogs with sensitivities to common meat proteins. It’s about both the source and the process. Their hydrolyzation process ensures that the soy proteins are broken down into very small fragments.

Hill’s, on the other hand, uses hydrolyzed chicken. This can be particularly beneficial for dogs who may be allergic to beef or lamb but can tolerate chicken if it’s sufficiently processed to remove allergenic properties. Hill’s focuses on making their diets extremely digestible, which can aid in nutrient absorption and reduce the workload on the gastrointestinal tract.

Q: Is there a difference in how dogs might react to soy versus chicken as a protein source?

Dr. Norton: Definitely. The protein source can influence both the palatability and how well a dog tolerates the diet. Some dogs might find chicken more palatable, which is crucial for maintaining appetite, while others might react better to soy due to specific meat allergies. It’s about finding a balance between a dog’s individual allergies, their taste preferences, and their overall health. Each dog is unique, so while one might thrive on a soy-based diet, another might do better with chicken, even in its hydrolyzed form.

Q: For pet owners considering these diets, what should they keep in mind about long-term feeding?

Dr. Norton: When it comes to long-term feeding of specialized diets like these, the key is monitoring. Owners should watch for any changes in their dog’s symptoms, weight, and overall behavior. Regular check-ups with the vet are crucial to ensure the diet continues to be appropriate for their health needs. Additionally, because these are specialized diets, they are often more expensive than regular dog food, so financial planning for pet care becomes even more important.

Q: Any final advice for dog owners navigating the choice between these two diets?

Dr. Norton: My biggest piece of advice is to work closely with your veterinarian. They can help you navigate the choice based on your dog’s specific health profile. Also, be patient. Sometimes, finding the right diet involves some trial and error. And once you find a diet that works, sticking to it consistently is crucial for maintaining your dog’s health.


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