The Truth About Collagen Types (I, II, III Explained)

You're looking at joint supplements and every brand makes different claims.

"Type II collagen is best for joints."
"You need all three types."
"Our blend contains 28 collagen types."

Here's what they're not telling you: Most of this is marketing, not science.

Let's explain what collagen types actually are, what they do, and which ones your dog really needs.

 

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What Are Collagen Types?

Your dog's body contains 28 different types of collagen.

Wait, 28?

Yes. But don't panic. Only 3 matter for supplementation.

Think of collagen types like different LEGO bricks:

They're all made from the same basic material (amino acids), but they're shaped differently and used in different structures.

The three most important:

Type I: 90% of your dog's total collagen
Type III: 5-10% of total collagen (usually found with Type I)
Type II: Less than 5% of total collagen (specific to cartilage)

 

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Type I Collagen: The Foundation

Where it's found:

• Skin (90%)

• Bones (90%)

• Tendons (95%)

• Ligaments (90%)

• Organs

• Blood vessels

• Teeth

What it does: Provides strength and structure. It's the load-bearing collagen.

Molecular structure: Thick, tightly-packed fibers. Like steel cables.

Why it's important for joints

Most people miss this: Joints aren't just cartilage.

A healthy joint has:

• Cartilage (cushioning)

• Tendons (attach muscle to bone) - Type I collagen

• Ligaments (connect bones) - Type I collagen

• Joint capsule (wraps the joint) - Type I collagen

• Synovial membrane (produces joint fluid) - Type I collagen

If you only supplement Type II (cartilage collagen), you're ignoring 80% of the joint structure.

 

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Type III Collagen: The Partner

Where it's found:

• Skin (alongside Type I)

• Blood vessels

• Intestines

• Organs

• Muscles

What it does: Provides elasticity and support. It's the flexible scaffolding.

Molecular structure: Thinner, more flexible fibers. Like elastic bands.

Why Types I and III work together

They're almost always found in the same tissues.

In skin:

• Type I provides strength

• Type III provides elasticity

• Together: strong but flexible skin

In blood vessels:

• Type I provides structure

• Type III allows expansion/contraction

• Together: vessels that don't rupture under pressure

In joint capsules:

• Type I provides stability

• Type III allows movement

• Together: joints that are stable but mobile

You rarely find one without the other.

 

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Type II Collagen: The Specialist

Where it's found:

• Cartilage (90% of cartilage is Type II)

• Vitreous body of eye

• Nowhere else

What it does: Provides cushioning in joints. Absorbs shock.

Molecular structure: Thin, loosely-packed fibers arranged in a mesh. Like a sponge.

Why it's specific to cartilage

Cartilage needs to:

• Compress under load

• Spring back to original shape

• Trap water (for cushioning)

Type II's structure is perfect for this job.

The marketing myth:

"Type II collagen is best for joints because joints contain cartilage."

The reality:

Joints need all their components healthy, not just cartilage.

Focusing only on Type II ignores:

• Tendon strength (Type I)

• Ligament stability (Type I)

• Joint capsule flexibility (Type I and III)

• Synovial membrane health (Type I)

 

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The Big Question: Which Type Should You Supplement?

Here's where science contradicts marketing.

What the marketing says:

"Type II collagen is best for joints because joints contain Type II collagen."

Sounds logical, right?

What the science shows:

Studies prove that Types I and III collagen peptides stimulate cartilage production even though they're not Type II.

How is this possible?

Two mechanisms:

1. Providing building blocks

All collagen types are made from the same amino acids:

• Glycine (33%)

• Proline (12%)

• Hydroxyproline (12%)

• Plus others

When you supplement Types I and III collagen peptides, you're providing these amino acids.

Your dog's body can then use these amino acids to make any type of collagen it needs, including Type II.

Think of it like: Giving your dog LEGO bricks. They can build whatever structure they need.

2. Signalling cartilage cells

This is the fascinating part.

When collagen peptides are absorbed, they don't just provide raw materials. They actively signal cells to increase collagen production.

Study by Oesser & Seifert (2003):

Researchers exposed cartilage cells (chondrocytes) to Types I and III collagen peptides (not Type II).

Results:

• Type II collagen synthesis increased by 60%

• Proteoglycan synthesis increased by 40%

Translation: Types I and III peptides told cartilage cells to make more Type II collagen.

3. Supporting the entire joint structure

Remember: Joints are more than cartilage.

By supplementing Types I and III, you're supporting:

• Cartilage (through signaling mechanism above)

• Tendons

• Ligaments

• Joint capsule

• Synovial membrane

You're rebuilding the entire joint, not just one component.

 

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The Type II Collagen Exception: Undenatured Collagen

There IS one form of Type II collagen that works differently.

Undenatured Type II collagen (UC-II):

What it is: Native (not broken down) chicken cartilage collagen

How it works: Completely different mechanism from hydrolysed peptides.

Not absorbed. Instead, it's taken up by immune cells in the gut and "teaches" the immune system to stop attacking joint tissue.

Effective dose: 10-40mg daily (tiny amount compared to hydrolysed collagen)

When it works:

• Autoimmune arthritis (rare in dogs)

• Rheumatoid arthritis

• Immune-mediated joint disease

When it DOESN'T work:

• Regular osteoarthritis (the most common type, caused by wear and tear, not immune attack)

• Injury recovery

• Prevention

For most dogs with joint issues, undenatured Type II collagen is the wrong choice.

 

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So Which Type Should You Actually Give Your Dog?

For 95% of dogs: Types I and III hydrolysed collagen peptides.

Why:

1. They support the entire body

• Joints (cartilage + tendons + ligaments + capsule)

• Skin and coat

• Bones

• Gut lining

• Everything

2. They're proven to stimulate Type II collagen production

Even though they're not Type II themselves.

3. Higher doses are possible

You can give 2,000-6,000mg+ daily. This provides substantial building blocks.

4. Best bioavailability

Molecular weight 2,000-5,000 Da. Perfectly sized for absorption.

5. Most studied

Majority of clinical studies showing joint improvement used Types I and III peptides.

 

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What About "Multi-Collagen" Supplements?

Some products claim to contain Types I, II, III, V, X, and more.

The truth:

1. Most collagen sources naturally contain multiple types

Bovine collagen naturally contains:

• Type I (majority)

• Type III (some)

• Type V (trace amounts)

You don't need special processing to get "multiple types."

2. Trace amounts don't matter

If a supplement contains 6,000mg Type I, 500mg Type III, and 50mg Type V, the Type V is irrelevant.

The dose is too low to matter.

3. Marketing over substance

"28 collagen types" sounds impressive but is meaningless.

Focus on:

• Total collagen content (milligrams)

• Molecular weight (2,000-5,000 Da for absorption)

• Types I and III primarily

Don't be distracted by lists of types in trace amounts.

 

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The Dose Matters More Than The Type

This is what most owners miss:

1,000mg of Type II collagen vs 6,000mg of Types I & III

Which is better for joints?

Answer: The 6,000mg.

Why?

Higher total dose means:

• More amino acid building blocks

• More signaling molecules reaching cartilage

• More substrate for body to use

Type matters less than quantity (assuming it's hydrolysed and absorbable).

Clinical studies showing joint improvement typically use 2,000-6,000mg+ daily.

Low-dose supplements (under 1,000mg) show minimal effects regardless of type.

 

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Pat's Pet Kitchen: Why We Use Types I & III

We chose Types I and III because:

1. Science supports it

Proven to stimulate cartilage production plus support entire joint structure.

2. Higher doses possible

Our Pure Collagen provides 6,000mg per serving. You can't get that with Type II sources.

3. Whole-body benefits

Supports skin, coat, gut, bones as bonus.

4. Cost-effective

Types I and III from bovine sources are high-quality and affordable, allowing us to provide therapeutic doses.

5. Proven results

Our customers report significant improvements in mobility, coat quality, and overall vitality.

Pure Collagen:

• 6,000mg Types I & III hydrolysed collagen peptides

• Low molecular weight (absorbable)

• From grass-fed cattle

• Nothing else

Mobility & Joints:

• 2,500mg Types I & III collagen peptides

• Plus glucosamine, hyaluronic acid, vitamins

• Comprehensive joint support

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

 

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How to Read Supplement Labels

Red flags:

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

❌ "Type II undenatured collagen" as primary ingredient
Wrong mechanism for most joint problems.

❌ Low dose (under 1,000mg total)
Not enough to matter.

❌ "Proprietary blend" without individual amounts
They're hiding the fact that most ingredients are in tiny amounts.

❌ Focus on number of types rather than total milligrams
Marketing gimmick.

Green flags:

✅ "Hydrolysed collagen peptides"
Correct form for absorption.

✅ "Types I and III" or "from bovine/marine source"
(Bovine = Types I & III, Marine = Type I primarily)

✅ High dose (2,000-6,000mg+)
Therapeutic range.

✅ Molecular weight 2,000-5,000 Da stated
Shows they tested for bioavailability.

✅ Clear label showing exact amounts
Transparency.

 

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The Bottom Line on Collagen Types

What you need to know:

1. Types I and III make up 95%+ of your dog's collagen

2. They support:

• The entire joint structure (not just cartilage)

• Skin and coat

• Bones

• Gut lining

• Overall connective tissue

3. They stimulate

Type II collagen production in cartilage Even though they're not Type II themselves.

4. Higher doses are possible and beneficial

6,000mg of Types I & III beats 500mg of Type II.

5. They're proven in clinical studies

Most research showing joint improvement used Types I & III peptides.

For most dogs, Types I and III hydrolysed collagen peptides are the right choice.

 

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Common Questions

"Should I give my dog Type II collagen for joints?"

Only if they have autoimmune arthritis (rare). For regular wear-and-tear osteoarthritis, Types I and III are superior.

"What about marine collagen vs bovine collagen?"

Marine (fish): Primarily Type I, smaller molecular weight (fastest absorption) 

Bovine (cattle): Types I and III, slightly larger peptides

Both work well. Bovine is more cost-effective for high-dose supplementation.

"Can I give my dog human collagen supplements?"

Yes, if they're pure hydrolysed collagen peptides without added flavoring or sweeteners.

But: Human supplements are expensive for the dose a large dog needs. Dog-specific formulations are more cost-effective.

"My vet recommended Type II collagen. Are they wrong?"

Not wrong, just possibly uninformed about the latest research.

Many vets learned "Type II for cartilage" in school and haven't seen the studies showing Types I & III stimulate cartilage production.

Show them: Oesser & Seifert (2003) study proving Types I & III peptides increase Type II collagen synthesis by 60%.

"What about collagen from bone broth?"

Beef Bone Broth contains:

• Types I and III collagen (from bones and connective tissue)

• Gelatin (partially hydrolysed collagen)

• Natural minerals

Great for: Whole-food approach, gut health, picky eaters

Different from: Pure hydrolysed peptides (lower collagen content per serving, not fully hydrolysed)

Can be used together for maximum collagen intake.

 

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Start With What Works

Don't be confused by marketing claims about collagen types.

Focus on:

• Hydrolysed collagen peptides (absorbable)

• Types I and III (support everything)

• High dose (2,000-6,000mg+)

• From reputable source

Your dog needs:

Prevention or mild issues:
Pure Collagen - 6,000mg Types I & III

Existing joint problems:
Mobility & Joints - 2,500mg collagen + joint-supporting ingredients

Whole-food approach:
Beef Bone Broth - 40% collagen content plus gelatin and minerals

The science is clear. The choice is simple.

 

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Sources & Further Reading

1. Shoulders MD, Raines RT. "Collagen structure and stability." Annual Review of Biochemistry, 2009

2. Eyre DR. "Collagen of articular cartilage." Arthritis Research, 2002

3. Byers PH. "Ehlers-Danlos syndrome." Journal of Investigative Dermatology, 1994

4. Eyre DR, Wu JJ. "Collagen structure and cartilage matrix integrity." Journal of Rheumatology, 1995

5. Oesser S, Seifert J. "Stimulation of type II collagen biosynthesis." Cell and Tissue Research, 2003

6. Crowley DC, et al. "Safety and efficacy of undenatured type II collagen." International Journal of Medical Sciences, 2009

7. Dar QA, et al. "Daily oral consumption of hydrolyzed type 1 collagen is chondroprotective." Osteoarthritis and Cartilage, 2017

Last Updated: December 2025