Collagen Type I & III: what do they mean?

Type I and Type III are two members of the collagen family. They are often mentioned together because both occur in connective tissues such as skin, while each also has its own distribution and structural role.

On a collagen supplement, the words “Type I & III” describe the collagen types associated with the ingredient’s source. They should not be read as a promise that one type is “for skin” and the other is “for joints,” or that intact collagen fibres remain unchanged after hydrolysis.

What are collagen types?

Collagen is a family of related structural proteins rather than one single substance. Researchers have identified many collagen subtypes, with Types I, II and III among the best-known fibrillar collagens.

The type number refers to molecular differences in the collagen protein. Those differences are linked to where the collagen is found and how it is organised within tissues.

What is Type I collagen?

Type I is the most abundant collagen type in the human body. It is widely distributed and is prominent in tissues such as skin, bone and tendon.

Its presence across several tissues is an important reason not to reduce Type I to a single consumer-friendly label such as “skin collagen” or “bone collagen.” Those descriptions are too narrow.

What is Type III collagen?

Type III is another fibrillar collagen. It is found in skin and blood vessels and is also an important structural component of several hollow organs.

Type III frequently occurs alongside Type I. Research on Type III collagen describes the two types as being associated in a range of tissues rather than functioning as completely separate systems.

Why are Type I and Type III often mentioned together?

They are commonly grouped because their tissue distribution overlaps. Skin is a familiar example, but Type I and Type III can also occur together in other connective tissues.

That does not mean the two proteins are identical. Native Type I and Type III collagen have different molecular structures and can contribute differently to the organisation of collagen fibrils.

For a supplement label, however, the practical message is simpler: “Type I & III” describes the collagen types connected with the source material.

How is Type II collagen different?

Type II is also a fibrillar collagen, but it is strongly associated with cartilage and related tissues.

This is why Type II frequently appears in discussions about cartilage, while Types I and III are more commonly associated with sources rich in skin and other connective tissues.

These tissue associations are useful for understanding biology, but they should not be turned into automatic claims about what an oral supplement will do.

What does Type I & III mean after collagen is hydrolyzed?

Hydrolysis breaks the long collagen protein into smaller peptide fragments.

As a result, a hydrolyzed Type I & III collagen ingredient should not be pictured as a powder full of intact Type I and Type III fibres. The type designation refers back to the collagen source, while the finished ingredient consists of collagen-derived peptides.

For more on that process, see What are collagen peptides?.

Does the collagen type tell you how well a supplement works?

Not by itself.

The type designation tells you something about the ingredient’s origin and collagen profile. It does not establish the dose, peptide profile, processing quality, overall formulation or a health outcome.

Those factors should be considered separately rather than assuming that a particular Roman numeral automatically makes one product superior.

Can you target a specific tissue by choosing a collagen type?

That is too simple a way to describe oral collagen.

After ingestion, hydrolyzed collagen is processed during digestion, with amino acids and small peptides appearing in the circulation. Those components enter normal metabolism; the collagen type on the label does not function like a delivery address that sends the supplement unchanged to one specific tissue.

The collagen type is therefore useful ingredient information, but it should not be presented as a guaranteed tissue-targeting mechanism.

What about EU health claims?

In the European Union, a collagen type name is not the same as an authorised health claim.

EFSA previously assessed a proposed claim for collagen hydrolysate and maintenance of joints and concluded that a cause-and-effect relationship had not been established. That is one reason to keep collagen type descriptions separate from unsupported outcome claims.

Vitamin C has a different regulatory status. EU-authorised claims include that vitamin C contributes to normal collagen formation for the normal function of skin, bones and cartilage, provided the conditions of use are met.

Type I & III in the Primal Wolf formula

Primal Wolf Collagen uses hydrolyzed bovine collagen peptides Type I & III and combines them with vitamin C, hyaluronic acid and zinc.

We use the Type I & III description to explain the collagen ingredient, not as a shortcut for promising a specific result. The complete formula, current amounts, serving information and directions for use are available on the Primal Wolf Collagen product page.

Frequently asked questions

Is Type I collagen only found in skin?

No. Type I is widely distributed and is prominent in skin, bone, tendons and ligaments, among other tissues.

Is Type III collagen only found in skin?

No. Type III is found in skin, but also in blood vessels and several internal tissues and organs.

Is Type I better than Type III?

They are different collagen types with different molecular structures and tissue distributions. There is no useful general rule that makes one universally “better” than the other.

Is Type II the same as Type I or III?

No. Type II is a distinct collagen type and is strongly associated with cartilage. Types I, II and III all belong to the fibrillar collagen group, but they are not interchangeable.

Does hydrolyzed Type I & III collagen still contain intact collagen fibres?

No. Hydrolysis breaks the original collagen protein into smaller peptide fragments. The Type I & III designation describes the collagen source rather than intact fibres in the finished powder.

Learn more

What are collagen peptides?

Explore Primal Wolf Collagen

Sources

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