Updated September 25, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: “Hypoallergenic” cat foods are used to diagnose and manage food allergies. The most reliable are prescription hydrolyzed-protein diets, where proteins are broken into pieces too small to trigger the immune system, and prescription novel-protein diets using a protein your cat hasn’t eaten before. Over-the-counter “limited ingredient” foods are often contaminated with other proteins. A strict 8-week food trial is the only way to confirm food allergy.
Signs of food allergy in cats
- Itching, especially around the head and neck
- Overgrooming and hair loss
- Vomiting or diarrhea in some cats
- Signs year-round
Types of diets
- Hydrolyzed: most reliable for trials
- Novel protein: must truly be new to your cat
- Over-the-counter limited ingredient: may contain undeclared proteins
Running a food trial
- Feed only the trial diet for about 8 weeks
- No treats, table food, or flavored medications
- Keep indoor/outdoor cats from hunting
- Rechallenge with the old food to confirm
More: elimination diet plan.
What to avoid
- Blood, hair, or saliva “allergy tests” for food
- Frequent diet switching
- Assuming grain-free means hypoallergenic
Sources
- Olivry T, Mueller RS. Critically appraised topics on adverse food reactions of companion animals: duration of elimination diets. BMC Vet Res. 2015
- Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Vet Res. 2016
- Merck Veterinary Manual: Food allergy in small animals
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.