Is Royal Canin Hydrolyzed Protein Good for Food Allergies?
Updated November 6, 2026
Often, yes, in a vet-run food trial of at least 8 weeks, though not for every dog. HP's soy protein is broken into small pieces that allergic dogs react to less. If your dog reacts to soy or chicken, ask your vet about Ultamino first. Our pick is HP, about $3.76 a day for a 50 lb dog.
Royal Canin Veterinary Diet Hydrolyzed Protein HP, 25.3 lb
$142.99 on Amazon (November 11, 2026), about $3.76 a day for a 50 lb dog
The standard adult formula: protein from hydrolyzed soy, carbs from brewers rice, 19% protein and 17% fat. A vet diet, so check with your vet first.
Check price on Amazon →- Built for food trials. 6 of Royal Canin's 7 hydrolyzed dog formulas build their protein around hydrolyzed soy, broken into small pieces that allergic dogs react to less often than whole proteins.
- Backed by studies, with limits. Hydrolyzed diets reduced, but did not remove, flares in some dogs, and a 2010 vet review found up to half of allergic dogs still reacted to a partial hydrolysate made from a food they were allergic to.
- Ultamino as the next step. Royal Canin calls its poultry protein "extensively hydrolyzed." It costs about $6.21 a day for a 50 lb dog in the 8.8 lb bag.
What does the research say about hydrolyzed dog food?
Hydrolyzed diets reduced, but did not remove, allergic flares in some dogs, and the protein source matters. These are the studies, from their PubMed abstracts.
- Soy-allergic dogs, 2003: as a group, 14 dogs with known soy and corn allergy itched significantly more after eating cornstarch, corn and soy, but not after a diet of hydrolyzed soy protein and cornstarch (Jackson and others, Veterinary Dermatology).
- Systematic review, 2010: hydrolyzed diets reduced or ended signs in a variable share of allergic dogs, but "up to 50%" of allergic dogs in three controlled studies got worse on partial hydrolysates made from foods they were allergic to. The authors advise these diets for dogs not known to be allergic to their ingredients (Olivry and Bizikova).
- Chicken-allergic dogs, 2016: in a blinded crossover trial of 10 chicken-allergic dogs, none flared on a hydrolyzed poultry-feather diet, while 4 of 10 flared on a hydrolyzed chicken-liver diet; each was fed for 14 days (Bizikova and others).
- How long a trial takes, 2015: more than 80% of food-allergic dogs went into remission by 5 weeks on an elimination diet, and more than 90% of dogs and cats by 8 weeks; the review advises at least 8 weeks (Olivry, Mueller and Prelaud).
- Label accuracy, 2018: a review found unlisted ingredients in 33% to 83% of store "novel" or "limited ingredient" foods tested, against one possible case among hydrolyzed diets (Olivry and Mueller; the authors report Royal Canin funding).
Which Royal Canin hydrolyzed food is which?
Royal Canin makes 7 hydrolyzed protein dog foods; 6 use hydrolyzed soy and one, Ultamino, uses hydrolyzed poultry. One row each, from royalcanin.com, read November 6, 2026. The pick is the blue row. On a phone, swipe the table sideways.
| Formula | For | Protein / fat min | Calories | First 4 ingredients | Cost a day, 50 lb dog |
|---|---|---|---|---|---|
| Hydrolyzed Protein HP | adult | 19% / 17% | 324 a cup | Brewers rice, hydrolyzed soy protein, chicken fat, natural flavors | $3.76 (25.3 lb bag) |
| Hydrolyzed Protein Small Dog | adult, small dogs | 22% / 14% | 375 a cup | Brewers rice, hydrolyzed soy protein, chicken fat, natural flavors | $5.44 (8.8 lb bag) |
| Hydrolyzed Protein Moderate Calorie | adult, fewer calories | 21% / 10% | 306 a cup | Brewers rice, hydrolyzed soy protein, chicken fat, natural flavors | not priced here |
| Hydrolyzed Protein PS | adult | 19% / 10% | 302 a cup | Brewers rice, hydrolyzed soy protein, chicken fat, natural flavors | not priced here |
| Ultamino | adult | 16.5% / 14.5% | 323 a cup | Corn starch, hydrolyzed poultry by-products aggregate, coconut oil, vegetable oil | $6.21 (8.8 lb bag) |
| Hydrolyzed Protein loaf (can) | adult | 5% / 1.5% (wet, 77.3% moisture) | 340 a can | Water sufficient for processing, pea starch, hydrolyzed soy protein, powdered cellulose | not priced here |
| Hydrolyzed Protein Puppy | puppy | 21% / 17% | 375 a cup | Brewers rice, hydrolyzed soy protein, chicken fat, natural flavors | not priced here |
Every formula's label says it "is formulated to meet" AAFCO nutrient levels (adult maintenance; puppy: growth). Cost a day = the calories a typical 50 lb adult dog needs (1,164 a day, from the NRC/WSAVA formula on our methodology page) at each bag's Amazon cost per calorie. Your vet's feeding amount comes first. Royal Canin also makes three combination diets for dogs with a second problem: Gastrointestinal Low Fat + Hydrolyzed Protein, Satiety + Hydrolyzed Protein, Renal Support + Hydrolyzed Protein.
Amazon prices as of 2026-11-11. Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply to the purchase of this product.
How much does Royal Canin HP cost a day?
About $3.76 a day for a 50 lb dog and $1.89 for a 20 lb dog, from the 25.3 lb Amazon bag ($5.65 a pound on November 11, 2026).
- How we got it: HP has 3,855 calories per kg. A 50 lb dog needing about 1,164 calories eats about 302 g a day, about 3.6 cups at 324 calories a cup.
- Per 1,000 calories: $3.23 for HP, $5.33 for Ultamino and $4.68 for HP Small Dog, at the bag sizes in the table.
What is in Royal Canin HP?
- Protein: hydrolyzed soy protein, which Royal Canin says is "composed of low molecular weight peptides."
- Carbohydrate: brewers rice is the first ingredient.
- Fat and flavor: chicken fat (third) and natural flavors (fourth). Every soy-based dry formula lists chicken fat. Ultamino uses coconut and vegetable oil instead, and the canned loaf lists hydrolyzed chicken liver.
- Protein level: 19% minimum (21.2% dry matter).
Which one should I ask my vet about?
- An adult dog starting a food trial, with no known soy or chicken allergy: Hydrolyzed Protein HP, about $3.76 a day for a 50 lb dog.
- Dogs known to react to soy or chicken, or that did not improve on HP: Ultamino, about $6.21 a day for a 50 lb dog.
- Small dogs: Hydrolyzed Protein Small Dog, about $2.74 a day for a 20 lb dog.
- Dogs that gain weight easily: Hydrolyzed Protein Moderate Calorie, 306 calories a cup against 324 for HP.
- Puppies: Hydrolyzed Protein Puppy, the only one of the 7 with an AAFCO growth statement.
- Other hydrolyzed vet diets: Purina Pro Plan Veterinary Diets HA and Hill's Prescription Diet z/d, which Amazon lists as a hydrolyzed chicken recipe. Also see best dog food for allergies.
Questions owners ask about Royal Canin Hydrolyzed Protein
Do I need a prescription for Royal Canin Hydrolyzed Protein?
Royal Canin sells it as a veterinary diet. Its product page says to consult your veterinarian and to buy it from a trusted partner "if you have a prescription." Amazon sells the bags, but plan on your vet's OK, and use the diet as part of a food trial your vet sets up.
Does Royal Canin HP have chicken in it?
Not as protein: the protein in HP is hydrolyzed soy. But HP lists chicken fat third and natural flavors fourth, and the canned loaf lists hydrolyzed chicken liver. If your dog is allergic to chicken, ask your vet before starting HP. Ultamino lists no chicken fat before its vitamin mix; its protein is extensively hydrolyzed poultry and its fats are coconut and vegetable oil.
How long until Royal Canin HP works?
Give it at least 8 weeks. A 2015 vet review found more than 80% of food-allergic dogs went into remission by 5 weeks on an elimination diet, and more than 90% of dogs and cats by 8 weeks, so it advises trials of at least 8 weeks. During the trial your dog eats only the trial food and treats your vet approves.
What is the difference between Royal Canin HP and Ultamino?
HP uses hydrolyzed soy protein. Ultamino uses "extensively hydrolyzed" poultry protein made of "oligopeptides and pure amino acids," per Royal Canin, and a production process meant to "avoid cross-contamination." Ultamino has 16.5% protein against 19% for HP and costs about $6.21 a day for a 50 lb dog against $3.76 (8.8 lb and 25.3 lb Amazon bags).
Is Royal Canin HP better than a limited-ingredient food from the store?
Hydrolyzed diets had far fewer unlisted ingredients in one review. That 2018 review found ingredients not on the label in 33% to 83% of store "novel" or "limited ingredient" foods tested, but only one possible case among the hydrolyzed diets tested. (The authors disclose funding from Royal Canin.)
Has Royal Canin been recalled?
In April and May 2007, Royal Canin recalled some dry foods made with imported rice protein that held a melamine compound; the vet diets named were Early Cardiac, Skin Support and a cat hypoallergenic food, not the dog Hydrolyzed Protein line. There is no Royal Canin recall in FDA's animal and veterinary recall list from 2019 on (checked November 6, 2026).
More: Royal Canin dry food alternatives · Royal Canin recall history · Royal Canin brand record · which Royal Canin vet diet? · all comparisons.
Sources
- Labels: each formula's page on royalcanin.com (linked from the table), read November 6, 2026: guaranteed analysis, calories, AAFCO statement and ingredients.
- Studies: PubMed abstracts 12895222, 19552700, 26310322, 27307314 and 29357847, linked above.
- Prices: Amazon, through Amazon's product API, sold by Amazon.com, on the date shown.
- Recalls: FDA's 2007 Royal Canin notices (archived) and FDA's animal and veterinary recall list from 2019 on.
- Not checked: Royal Canin cat diets, Purina HA and Hill's z/d labels, and whether any food suits your dog. A food trial should be planned with your vet.