Pet Food Ingredient
Hydrolyzed Soy
Soy protein broken into peptide fragments. Used as the primary protein source in several Rx hypoallergenic formulas, notably Royal Canin Ultamino and Purina Pro Plan HA.
Also labelled as
Regulatory status
Classified under AAFCO processed vegetable proteins; specific Rx-diet formulations require vet authorisation.
Key notes
- —Works for dogs with combined animal-protein sensitivities because no animal-derived allergen is present.
- —Hypoallergenic status depends entirely on hydrolysis depth. Undhydrolysed soy is itself a known allergen (6-10% of food-allergic dogs) so the fragment size matters.
Common alternatives
In-depth guides
Common questions
Is hydrolyzed soy the same as regular soy for allergic dogs?
No — the hydrolysis is the key difference. Regular soy is a known dog food allergen (6-10% of food-allergic dogs react). Hydrolyzed soy is broken into peptide fragments small enough to escape most IgE responses. Royal Canin Hydrolyzed Protein HP and Purina Pro Plan HA use hydrolyzed soy as the primary protein source for this reason.
Why do Rx hypoallergenic foods use soy instead of meat?
Hydrolysis is more reliable and cheaper with soy than with animal proteins. Soy protein is a uniform commodity that hydrolyses predictably. Animal proteins (chicken, beef) hydrolyse but cost more and have more batch-to-batch variation. For dogs with multiple confirmed animal-protein allergies, hydrolysed soy removes all animal-protein exposure at once, which is useful diagnostically.
Is this ingredient in your pet's food?
Scan the label. If it contains hydrolyzed soy or any of the alternative names above, the scanner will flag it against your pet's allergen profile.
Scan a label →This entry is factual reference. It is not medical or veterinary advice. Consult a veterinarian for any decisions about your pet's diet.