If your dog is scratching constantly, struggling with loose stools, or suffering from recurring ear infections, a food allergy or intolerance could be to blame. Hydrolysed dog food is widely recommended by vets as the gold standard for managing food-related allergies — and in this guide, we break down how it works, what to look for, and which UK recipes are worth trying.

Not sure if allergies are the issue? Use our free hydrolysed dog food checker to match your dog’s symptoms to the right recipe.

What Causes Food Allergies in Dogs?

Most food allergies in dogs are a reaction to protein. The immune system recognises a protein molecule as a threat and triggers an inflammatory response — causing symptoms that can show up in the skin, gut, ears, or coat. Common culprits include beef, chicken, dairy, wheat, and eggs, though a dog can develop a sensitivity to almost any protein they’ve been exposed to repeatedly over time.

Symptoms vary widely between dogs. Itchy skin, hot spots, and hair loss are the most common signs, but digestive problems (loose stools, gas, vomiting), recurring ear infections, and persistent paw licking are also frequently linked to food intolerances. Many dogs show a combination of both skin and gut symptoms.

Why Hydrolysed Dog Food Works for Allergies

Hydrolysed dog food works by breaking protein down into fragments so small the immune system simply cannot recognise them as a threat. This process — hydrolysis — happens before the food is manufactured, using natural plant enzymes to pre-digest the meat or fish into tiny peptide chains.

The result is a protein that delivers full nutrition without triggering an immune reaction. It is not the same as a novel protein diet (where you switch to a protein your dog hasn’t eaten before). It goes further than that — the protein is made invisible to the immune system regardless of what your dog has eaten in the past. This is why it is the approach most often recommended for dogs with multiple intolerances or unknown sensitivities.

What to Look for in a Hydrolysed Dog Food for Allergies

Not all hydrolysed dog foods are equal. When choosing one for a dog with allergies, look for:

• Genuinely hydrolysed protein — the primary meat or fish should be hydrolysed, not just listed as a minor ingredient in an otherwise standard recipe
• Single protein source — reduces the risk of cross-reactivity and makes it easier to identify what your dog is reacting to
• Grain-free formulation — sweet potato or potato as the carbohydrate base is gentler for dogs with sensitive digestion
• No prescription required — many clinical hydrolysed diets require vet authorisation, but effective options are available to buy directly
• UK manufactured and EU compliant — ensures the food meets UK and EU nutritional standards for complete and balanced feeding

Best Hydrolysed Dog Foods for Allergies in the UK

1. Ultimate Plus Hydrolysed Skin & Coat Care — Best for Skin Allergies

Best for: itchy skin, hot spots, recurring ear infections, dull or dry coat

Made with 26% freshly prepared hydrolysed salmon, this recipe has 64% of its protein broken into fragments too small for the immune system to react to. It also delivers a targeted blend of Omega-3 and Omega-6 fatty acids from borage, salmon, and soya oil — each targeting a different mechanism of skin inflammation. Collagen peptides support the skin barrier structure from the inside.

In a feeding trial, 75% of owners reported visible improvement in their dog’s skin and coat condition. No prescription required. Grain-free, available in 1.5kg and 10kg.

Shop Hydrolysed Skin & Coat Care →

2. Ultimate Plus Hydrolysed Digestive Care — Best for Gut-Related Allergies

Best for: loose stools, chronic diarrhoea, IBD, food intolerance with digestive symptoms, excess gas

If your dog’s allergy primarily shows up as digestive upset, this turkey-based recipe was independently measured at 95% protein digestibility in a live feeding study at Ghent University Vet School — rated excellent against FEDIAF guidelines. TruPet™ postbiotic and collagen peptides (1.9%) support gut wall integrity and a healthy microbiome.

Shop Hydrolysed Digestive Care →

3. Ultimate Plus Hydrolysed Healthy Living — Best for Unknown or Multiple Allergies

Best for: dogs with unknown sensitivities, multiple intolerances, puppies, seniors, or as a long-term maintenance diet

If you’re not sure which protein your dog is reacting to, the Healthy Living recipe is the safest starting point. It suits all life stages (the only Ultimate Plus recipe approved for puppies), and its antioxidant salmon peptides reduced free radicals by 75% in a 2024 University of Liège study — reducing the overall inflammatory load that can make allergy symptoms worse.

Shop Hydrolysed Healthy Living →

How to Run an Allergy Elimination Trial

Choosing the right food is only half the job. The trial process matters just as much:

1. Pick one recipe and stick to it — no mixing, no treats, no table scraps. Any other protein in the diet during the trial will compromise the results.
2. Run the trial for at least 8 weeks — switching too early or mixing proteins will give inconclusive results. Most owners see meaningful improvement by weeks 3–5, but the full 8 weeks is needed to be sure.
3. Monitor symptoms weekly — keep a simple note of skin condition, stool firmness, energy levels, and ear health.
4. If improvement is clear, maintain the diet — hydrolysed food is safe for long-term everyday feeding. You do not need to cycle off it.

If symptoms do not improve after an 8-week exclusive trial, the issue may not be food-related and a vet visit is advisable to investigate environmental or contact allergies.

Frequently Asked Questions

Is hydrolysed dog food good for all types of allergies?

It is most effective for food-related allergies and intolerances. If your dog’s symptoms are environmental (pollen, grass, dust mites), hydrolysed food may reduce the overall inflammatory load but will not resolve the root cause.

Do I need a vet prescription for hydrolysed dog food?

Not for Ultimate Plus. Unlike prescription hydrolysed diets such as Royal Canin HP or Hill’s z/d, our full range is available to buy directly without vet authorisation — so you can start your dog’s trial straight away.

How long does it take for hydrolysed dog food to work?

Most owners notice early improvement within 2–5 weeks depending on the symptom. Skin improvements typically take a little longer than digestive ones. Allow the full 8 weeks before drawing conclusions.

Can I feed hydrolysed dog food long term?

Yes. All Ultimate Plus hydrolysed recipes are formulated as complete and balanced everyday diets, not short-term therapeutic feeds. Many dogs stay on them permanently once owners see the results.

Can puppies eat hydrolysed dog food?

Yes — the Hydrolysed Healthy Living recipe is approved for all life stages including puppies, adults, and seniors.

The Bottom Line

Hydrolysed dog food is the most reliable dietary tool available for managing food allergies in dogs — and unlike prescription diets, you do not need a vet referral to access it. The key is choosing a recipe matched to your dog’s primary symptom and running a proper 8-week exclusive trial.

Not sure which recipe is right for your dog? Use our free hydrolysed dog food checker — answer a few quick questions about your dog’s symptoms and we’ll point you to the right recipe.