Hill's Prescription Diet z/d Low Fat 17.6 lb Hydrolyzed Soy Bag

In this review we look at Hill's Prescription Diet z/d Low Fat Hydrolyzed Soy Recipe, a 17.6 lb clinical dry food formulated for dogs with food sensitivities. The bottom line: this diet is intended for pets that show skin or digestive reactions to common proteins and need a highly digestible, veterinary-grade formula. The review finds it most useful when fed under veterinary guidance because it replaces intact animal proteins with a hydrolyzed soy protein and includes targeted nutrients to support skin, digestion, and urinary health.

Key Features

• Hydrolyzed protein: Uses hydrolyzed soy protein to reduce the chance of triggering common food allergens and support digestion.
• Low fat formulation: Designed to limit fat intake for dogs that require a reduced-fat diet while still providing balanced nutrition.
• ActivBiome+ technology: Fortified with a proprietary ingredient to help activate the gut microbiome and promote normalized stool.
• Skin and immune support: Enriched with essential fatty acids and clinically proven antioxidants to help maintain a healthy skin barrier and immune system.
• Urinary support: Formulated to promote a urinary environment that reduces risk for struvite and calcium oxalate crystals.
• Veterinary formulation: Developed by nutritionists and veterinarians and sold as a prescription therapeutic diet for dogs with adverse food reactions.

Who It's For

This food fits dogs diagnosed with adverse food reactions where intact animal proteins are suspected or confirmed allergens, and for pets that need a low-fat, hydrolyzed-protein option. It is appropriate when a veterinarian recommends an elimination or hypoallergenic diet and wants a product that also supports skin and urinary health.

Owners seeking a general all-life-stage maintenance kibble or looking for a budget everyday food without veterinary oversight should look elsewhere, since this is a prescription therapeutic diet intended for specific clinical needs and may be priced higher than ordinary dry foods.

Pros & Cons

Pros

• Formulated with hydrolyzed soy protein to help avoid common food allergens and improve digestibility.
• Contains ActivBiome+ to support gut microbiome health and help normalize stool.
• Includes essential fatty acids and antioxidants to support skin barrier and immune function.

Cons

• Several customers noted the product can be costly, so value for money is mixed compared with non-prescription diets.

Specifications

Product	z/d Low Fat Hydrolyzed Soy Recipe dry dog food
Weight	17.6 lb bag
Protein source	Hydrolyzed soy protein (no intact animal proteins)
Special features	Low fat, ActivBiome+ gut support, urinary crystal risk reduction
Formulated by	Hill's nutritionists and veterinarians
Made in	USA with global ingredients

Our Verdict

Prescription Diet z/d Low Fat Hydrolyzed Soy Recipe is a targeted clinical option for dogs with food sensitivities that require a low-fat, hydrolyzed-protein diet. It pairs digestibility and microbiome support with skin and urinary health benefits, making it a sensible choice when recommended by a veterinarian, though cost-conscious buyers should weigh price versus therapeutic benefit.

Frequently Asked Questions

Is this food suitable for all dogs with allergies?
It is intended for dogs with adverse food reactions, especially when intact animal proteins are suspected; consult your veterinarian to confirm suitability.

Will this help digestive upset and stool consistency?
The formula includes ActivBiome+ and hydrolyzed protein to support digestion and help normalize stool, but results can vary by dog.

Does it prevent urinary crystals?
The diet is formulated to promote a urinary environment that reduces the risk of struvite and calcium oxalate crystal formation, but your vet should monitor urinary health.