Feline Urinary SO + Hydrolyzed Protein Dry Cat Food
Verified Jun 16, 2026
This is a veterinary therapeutic dry diet for adult cats that combines urinary support with a hydrolyzed protein source. It uses brewers rice as the main carbohydrate, hydrolyzed soy protein to reduce the risk of dietary reactions, and controlled minerals to help manage struvite and calcium oxalate crystals. The formula is designed for cats who need ongoing urinary care and may also have digestive or skin sensitivities related to food proteins.
Nutritionally, this is a well-designed therapeutic diet for cats needing both urinary support and a hydrolyzed protein source, such as those with a history of urinary crystals and suspected food-related skin or GI issues. The moderate protein and fat levels, controlled magnesium, and added omega-3 fish oil fit well with long-term use under veterinary supervision. It’s best suited for adult cats with specific medical needs rather than as a general maintenance food for healthy cats.
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At a Glance
KibbleLab Review
Strengths
- Hydrolyzed soy protein is highly digestible and can be very helpful for cats with suspected food allergies or sensitivities to intact proteins like chicken or beef.
- Formulated specifically to help manage struvite and calcium oxalate crystals by increasing urine volume and controlling mineral levels, including a low magnesium maximum of 0.06%.
- Includes fish oil and added fiber sources such as powdered cellulose and chicory root, which can support skin/coat and digestive health.
- Calorie density (about 334 kcal per cup) and moderate protein (25% min) and fat (14% min) are appropriate for many adult indoor cats when portions are controlled.
Considerations
- Primary protein is hydrolyzed soy, not animal protein; while appropriate for allergy management, some cats may prefer or do better on animal-based proteins when allergies are not a concern.
- Carbohydrate content is relatively high, with brewers rice listed first, which may not be ideal for all cats, especially those prone to weight gain if portions are not carefully managed.
- Contains chicken fat and fish oil, so it may not be suitable for cats with allergies to chicken or fish despite the hydrolyzed main protein source.
- As a prescription therapeutic diet, it should only be used under veterinary guidance, especially in cats without a confirmed urinary or food sensitivity issue.
Full Ingredient List
Ingredients and analysis reflect manufacturer data at the time of our last update and can change without notice. Always check the actual product packaging before feeding.
Ingredient filtering helps identify compatible options but is not a substitute for a veterinary elimination diet.
Top 5 Ingredients Explained
01
Brewer's Rice
Brewer’s rice is a milling byproduct of rice processing made up of small broken white rice kernels commonly used in pet foods as a highly digestible carbohydrate source, filler and binder that provides readily available energy for dogs and cats while contributing little protein, fat or fiber. It is generally gentle on the stomach and cost‑effective, but diets using it must supply other ingredients for essential nutrients; pet owners should note its relatively high glycemic load (relevant for weight or diabetic pets), the potential for trace environmental contaminants associated with rice, and not confuse it with brewer’s yeast.
02
Hydrolyzed Soy Protein
Hydrolyzed soy protein is a processed plant protein broken into small peptides and amino acids and is used in pet foods as a digestible protein source and flavor enhancer, often in hypoallergenic or limited‑ingredient formulations. It can improve digestibility and may reduce allergic reactions for some animals, but it may still trigger soy‑sensitive pets, does not supply certain nutrients cats need from animal proteins (e.g., taurine), and formulations should be evaluated for added sodium or flavoring compounds.
03
Chicken Fat
Chicken fat is used in dog and cat foods as a concentrated energy and flavor source that supplies essential fatty acids (notably linoleic acid) and aids absorption of fat‑soluble vitamins, improving palatability and supporting skin and coat health. Because it is calorie‑dense, diets must account for added fat to prevent weight gain, and quality (proper rendering and antioxidant protection to prevent rancidity) is important; although fats are less commonly allergenic than proteins, pets with poultry sensitivities may still react in some cases.
04
Cellulose Powder
Cellulose powder is an insoluble, plant-derived fiber commonly used in pet foods as a bulking agent, binder and calorie-diluting texturizer to help control weight and improve stool formation; it is not digestible by dogs or cats and contributes negligible energy or vitamins. While it can aid stool consistency and manufacturing performance, cellulose is non‑fermentable so offers little prebiotic benefit, and high inclusions can reduce palatability or displace nutrients—formulations, especially for cats with lower fiber tolerance, should be balanced accordingly.
05
Natural Flavor
Natural flavor is used primarily as a palatability enhancer in pet foods to improve taste and aroma and is not intended to provide significant nutrients, typically coming from concentrated extracts of meat, poultry, plant, or fermentation sources. While it can increase acceptance in picky dogs and cats, manufacturers are not required to disclose specific sources so pets with known sensitivities or allergies may react, and presence of natural flavor should not be taken as a guarantee of overall product quality.
Nutritional Breakdown
How to read As Fed versus Dry Matter
As fed shows the numbers straight off the label, water included. Dry matter removes the water so you can compare a wet food and a dry food fairly.What is calorie density
How many calories the food packs per unit. Denser foods mean smaller portions for the same calories.Product Details & Brand
Product Specs
Brand
Royal Canin is a premium pet food brand offering highly specific diets tailored to different breeds, life stages, sizes, and health conditions of dogs and cats. The brand is known for its science-driven approach and collaboration with veterinarians and pet professionals.
Visit Royal CaninWSAVA publishes criteria for evaluating a manufacturer (qualified nutritionists, feeding trials, published research); it does not certify or endorse brands.
Manufacturer
Royal Canin operates manufacturing facilities globally with strict quality control processes and adheres to ISO certification standards. The company maintains full traceability of ingredients, follows HACCP principles, and complies with local and international pet food safety regulations including EU and FDA requirements.
Manufacturing details are compiled from public sources and not independently verified; they may not reflect contract manufacturing or co-packing.
Recall History
Royal Canin Feline Urinary SO + Hydrolyzed Protein Dry Cat Food has no recalls since 2014.
Source: FDA Pet Food Recall Database · Monitored daily
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Frequently Asked Questions
Has Royal Canin ever been recalled?
We have no recalls on record for Royal Canin. We monitor the FDA Pet Food Recall Database daily.
How does KibbleLab rate foods?
Our scores are based on ingredient composition, nutritional profile, AAFCO compliance, and health considerations. We don't penalize by-products, grains, or synthetic preservatives. Brands cannot pay for higher scores.
Is KibbleLab a substitute for veterinary advice?
No. KibbleLab provides data-driven food analysis, not medical advice. Always consult your veterinarian before making dietary changes, especially for pets with health conditions.
KibbleLab provides informational content only. This is not veterinary advice. Always consult a qualified veterinarian before changing your pet's diet.
KibbleLab may earn affiliate commissions through product links. No one can pay for a higher score, or to change what we recommend for your pet.
Product data sourced from manufacturer websites, AAFCO statements, and FDA recall database. Last verified dates reflect our most recent data check.
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