What is Hydrolysed Collagen? (And Why It Matters for Your Dog)

You're comparing dog joint supplements.

One says "collagen." Another says "hydrolysed collagen peptides." Another says "undenatured collagen."

They all sound similar. The price differences are huge. Which one actually works?

Here's the truth: most collagen supplements don't do anything because your dog's body can't absorb them.

Let me explain why molecular size matters more than anything else.

 

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What is Collagen?

Collagen is a protein. The most abundant protein in your dog's body.

It makes up:

• 30% of total protein mass

• 90% of connective tissue

• 70% of skin

• 90% of tendons and ligaments

• The structural framework of bones

Think of collagen as scaffolding. It holds everything together. Without it, your dog would literally fall apart.

The problem: As dogs age, collagen production declines by 1-2% per year after age 5.

The result: Joints break down, skin loses elasticity, coat dulls, gut lining weakens.

The solution: Supplement with collagen to replace what they're losing.

But here's the catch: Not all collagen supplements work.

 

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The Absorption Problem

Standard collagen molecules are HUGE.

Molecular weight: 300,000 Daltons (Da)

For context:

• Water: 18 Da

• Glucose: 180 Da

• Vitamin C: 176 Da

• Collagen: 300,000 Da

Your dog's intestinal wall can only absorb molecules smaller than 5,000 Da.

Standard collagen is 60 times too large to pass through the gut wall.

What happens when you give your dog standard collagen:

1. They eat it

2. It travels through the stomach

3. It reaches the small intestine

4. It's too large to absorb

5. It exits in their faeces

You've just created expensive dog poop.

 

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What is Hydrolysed Collagen?

Hydrolysis = breaking something down with water and enzymes.

The process:

1. Start with raw collagen (from beef, pork, or fish)

2. Treat with enzymes (protease)

3. Break the massive collagen molecules into tiny pieces called peptides

4. Result: Collagen peptides with molecular weight of 2,000-5,000 Da

Now it's small enough to absorb.

Hydrolysed collagen = collagen peptides = bioavailable collagen

They all mean the same thing: collagen that's been broken down into absorbable pieces.

 

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How Hydrolysed Collagen is Made

Step 1: Source material

High-quality hydrolysed collagen comes from:

• Grass-fed cattle (bovine collagen)

• Wild-caught fish (marine collagen)

• Pork (porcine collagen)

At Pat's Pet Kitchen, we use grass-fed bovine collagen. No hormones, no antibiotics.

Step 2: Extraction

Collagen is extracted from connective tissue (hides, bones, cartilage) through controlled heating.

Step 3: Hydrolysis

The extracted collagen is treated with specific enzymes (proteases) that break the long collagen chains into short peptides.

The precision matters: Over-hydrolysis breaks peptides too small. Under-hydrolysis leaves them too large. Proper hydrolysis creates peptides between 2,000-5,000 Da.

Step 4: Purification

Peptides are filtered, purified, and dried into a powder.

Step 5: Testing

Reputable manufacturers test for:

• Molecular weight distribution (ensuring peptides are the right size)

• Protein content (should be 90%+ protein)

• Heavy metals, contaminants

• Microbial safety

The result: Pure collagen peptides that your dog's body can actually use.

 

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What Happens After Your Dog Eats Hydrolysed Collagen

The journey:

1. Stomach (10-30 minutes) Collagen peptides pass through the stomach relatively intact. Stomach acid doesn't break them down further because they're already small.

2. Small intestine (30-90 minutes) This is where absorption happens.

How it works:

• Peptides are small enough to pass through intestinal cells

• They enter the bloodstream intact

• Studies using radioactive markers prove this (they can track where peptides go)

3. Bloodstream Once in the blood, collagen peptides circulate throughout the body.

4. Target tissues This is the fascinating part. Studies show collagen peptides specifically accumulate in:

• Cartilage (joints)

• Skin

• Tendons and ligaments

• Bone matrix

How do they know where to go?

Researchers don't fully understand the mechanism, but the evidence is clear: collagen peptides preferentially accumulate in tissues that need them most.

5. Stimulation of collagen production

Once in the target tissue, collagen peptides:

• Provide amino acids (building blocks) for new collagen

• Stimulate fibroblasts (cells that produce collagen) to increase production

• Signal chondrocytes (cartilage cells) to make more cartilage matrix

This is why hydrolysed collagen works: it doesn't just provide raw materials. It actively signals the body to produce more collagen.

 

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Hydrolysed vs Undenatured vs Standard Collagen

Let's clear up the confusion.

Standard Collagen (Gelatin)

What it is: Intact collagen protein, molecular weight 300,000 Da

Can your dog absorb it? No. Too large.

Does it work? No, unless your dog has a severe protein deficiency (rare).

Cost: Usually cheapest, but useless.

Our verdict: Don't waste your money.

Hydrolysed Collagen (Collagen Peptides)

What it is: Collagen broken down into peptides, molecular weight 2,000-5,000 Da

Can your dog absorb it? Yes. Small enough to pass through gut wall.

Does it work? Yes. Proven in multiple clinical studies.

Mechanism:

• Absorbed intact

• Accumulates in target tissues

• Stimulates collagen production

• Provides building blocks for repair

Cost: More expensive than standard collagen, but worth it.

Our verdict: This is what works. This is what we use.

Undenatured Collagen (Type II Collagen)

What it is: Native (not broken down) Type II collagen, usually from chicken cartilage

Can your dog absorb it? Not really. Molecular weight is still large.

Does it work? Different mechanism. Some evidence for immune modulation in humans, limited evidence in dogs.

Mechanism (theoretical): Instead of being absorbed, it's supposed to "teach" the immune system to stop attacking joint tissue in autoimmune conditions.

When to use:

• Autoimmune arthritis (rheumatoid arthritis)

• Specific immune-mediated joint disease

When NOT to use:

• Regular osteoarthritis (the most common type)

• Injury recovery

• Prevention

Our verdict: Niche application. For most dogs with joint issues, hydrolysed collagen is superior.

 

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Why Molecular Size is Everything

Think of your dog's intestinal wall as a security gate with a specific-sized opening.

The opening size: 5,000 Da maximum

Standard collagen (300,000 Da): Trying to fit an elephant through a cat flap. Not happening.

Hydrolysed collagen (2,000-5,000 Da): Fits through perfectly.

This is why you can't just buy "collagen powder" from the health food store and expect it to work.

You need:

✅ Hydrolysed collagen (also called collagen peptides)
✅ Molecular weight 2,000-5,000 Da
✅ From a reputable manufacturer who tests for this

At Pat's Pet Kitchen:

• We only use hydrolysed collagen peptides

• Molecular weight confirmed between 2,000-5,000 Da

• Third-party tested for purity and safety

• No fillers, no additives

Because supplements that don't absorb are useless.

 

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Types of Collagen: I, II, III

Your dog's body contains 28 different types of collagen. The three most important:

Type I Collagen

Found in:

• Skin (90%)

• Tendons (95%)

• Ligaments (90%)

• Bones (90%)

• Organs

What it does: Provides structure and strength. It's the most abundant collagen in the body (90% of total collagen).

Type III Collagen

Found in:

• Skin (alongside Type I)

• Blood vessels

• Internal organs

• Gut lining

What it does: Provides elasticity and flexibility. Works alongside Type I.

Important: Types I and III are almost always found together in tissues.

Type II Collagen

Found in:

• Cartilage (90%)

What it does: Provides cushioning in joints. It's specific to cartilage.

The catch: Type II only makes up about 10% of total body collagen. It's important for joints, but it's not the whole story.

Which Type Should You Supplement?

The marketing myth: "Type II collagen is best for joints."

The reality: Joints need more than just cartilage.

A healthy joint requires:

• Cartilage (Type II collagen)

• Strong tendons and ligaments (Type I collagen)

• Flexible joint capsule (Type I and III collagen)

• Healthy synovial membrane (Type I and III collagen)

If you only supplement Type II, you're ignoring 90% of the joint structure.

 

Our approach at Pat's Pet Kitchen:

We use Types I and III collagen because:

1. They support the entire joint structure, not just cartilage

2. They're more abundant in the body (easier to source, higher doses possible)

3. Studies show they stimulate cartilage production even though they're not Type II

4. They support skin, coat, gut, and bones as a bonus

When properly hydrolysed, Types I and III peptides stimulate your dog's body to produce its own Type II collagen in cartilage.

 

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How Much Hydrolysed Collagen Does Your Dog Need?

Effective doses:

Small dogs (under 10kg): 2,000-3,000mg daily
Medium dogs (10-25kg): 4,000-6,000mg daily
Large dogs (over 25kg): 6,000-12,000mg daily

More is not always better. There's a threshold where additional collagen doesn't provide additional benefit. Please read the instructions for recommended dosage based on your dogs size.

At Pat's Pet Kitchen:

• Pure Collagen: 6,000mg per serving

• Mobility & Joints: 5,000mg collagen + glucosamine + hyaluronic acid + vitamins (comprehensive formula)

 

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How to Give Hydrolysed Collagen

Pure collagen peptides are:

• Tasteless

• Odourless

• Dissolve in liquid

• Mix invisibly into food

How to use:

1. Scoop recommended amount

2. Sprinkle on wet or dry food

3. Mix in (or don't, they won't notice)

4. Done

No chews. No tablets. No forcing it down their throat.

Just add to food. They'll eat it without knowing it's there.

Pro tip: If your dog is extremely fussy, mix with a small amount of water first to create a paste, then mix into food. Or try adding our Beef Bone Broth for extra flavour and natural mineral boost.

 

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How Long Before It Works?

Collagen isn't a painkiller. It's rebuilding tissue.

Timeline:

Week 1-2: No noticeable change (collagen is accumulating in tissues)

Week 3-4: Slight improvement in coat texture, reduced itching (skin responds fastest)

Week 4-6: Noticeable improvement in mobility. Easier getting up, less stiffness, more enthusiasm for walks.

Week 8-12: Maximum benefit achieved. Sustained improvement in joint comfort and function.

Important: Benefits only last as long as you continue supplementation. Stop giving collagen = collagen levels drop again within weeks.

This is a maintenance supplement, not a cure.

 

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Are There Side Effects?

Collagen is a food-derived protein. It's not a drug.

Side effects are extremely rare.

Reported occasionally:

• Mild digestive upset in the first few days (uncommon)

• Solution: Start with half dose for first week, then increase

Not reported:

• Allergic reactions (unless dog has known allergy to beef, pork, or fish)

• Liver or kidney issues

• Drug interactions

Long-term safety: Studies up to 2 years show no adverse effects from daily collagen supplementation.

Safe for:

• Puppies (over 6 months)

• Adult dogs

• Senior dogs

• Dogs on medications (always check with vet if on anticoagulants)

 

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How to Spot Quality Hydrolysed Collagen

Red flags (avoid these products):

❌ "Collagen" without "hydrolysed" or "peptides"
Likely standard collagen. Won't absorb.

❌ No information about molecular weight
If they don't mention 2,000-5,000 Da, they probably didn't test for it.

❌ Extremely cheap
Proper hydrolysis costs money. If it's half the price of competitors, ask why.

❌ Made in China (for pet supplements)
Quality control issues are common. Stick to UK, EU, or North American manufacturers.

❌ Long ingredient list
Pure collagen should be one ingredient: hydrolysed collagen. If there are 10 ingredients, most of it is filler.

❌ "Collagen complex" or "proprietary blend"
This is code for "we're not telling you how much of each ingredient is in here."

Green flags (what to look for):

✅ "Hydrolysed collagen peptides"
The exact wording you want to see.

✅ Molecular weight stated (2,000-5,000 Da)
Shows they've tested and care about absorption.

✅ High protein content (90%+ protein)
Pure collagen is almost entirely protein.

✅ Grass-fed bovine source
Better quality, no hormones or antibiotics.

✅ Made in UK or EU
Strict quality standards.

✅ Third-party tested
Independent verification of purity and potency.

✅ Transparent dosing
Tells you exactly how many milligrams per scoop.

 

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Pat's Pet Kitchen: Why We Use Hydrolysed Collagen

We could have used standard collagen. It would have been cheaper.

We could have used undenatured collagen. It would have sounded more scientific.

We chose hydrolysed collagen peptides because it's the only form with proven bioavailability and clinical efficacy.

Our formulas:

Pure Collagen:

• 6,000mg hydrolysed collagen peptides per serving

• Types I & III

• Molecular weight 2,000-5,000 Da

• From grass-fed cattle

• Made in England

• Nothing else

Mobility & Joints:

• 2,500mg hydrolysed collagen peptides

• Plus glucosamine, hyaluronic acid, vitamins

• Comprehensive joint support formula

Beef Bone Broth:

• 40% collagen content (naturally occurring in bone broth)

• Plus gelatin and minerals

• Whole-food approach

If it isn't good enough for us, it isn't good enough for them.

 

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The Bottom Line

Not all collagen supplements work.

Standard collagen: Too large to absorb. Expensive dog poop.

Hydrolysed collagen peptides: Small enough to absorb. Proven to work in clinical studies.

If the label doesn't say "hydrolysed" or "peptides," don't buy it.

Your dog deserves supplements that actually do something.

Always consult your vet when introducing new supplements.

Last Updated: December 2025