Bovine Collagen Type I and III: What the Difference Means

If you have picked up a tub of bovine collagen and noticed it says Type I and III on the label, you may have wondered whether that is meaningful or just marketing. It is meaningful. The two types are structurally distinct proteins that happen to co-exist in the same tissue, which is why bovine hide yields them together rather than separately.

What collagen types actually are

Collagen is not a single molecule. There are at least 28 distinct types identified in vertebrate biology, each encoded by different genes and assembled into different molecular architectures. What they share is a triple helix: three polypeptide chains wound around each other into a tight rope-like structure. What differs is which chains combine, how long the helical region is, and how the resulting fibrils organise themselves in tissue.

Type I is the most abundant collagen in the body and in the animal kingdom generally. Its triple helix is made from two alpha-1(I) chains and one alpha-2(I) chain. The resulting fibril is long, thick and tensile — suited to tissue that needs to resist pulling force. Type III is also fibrillar but uses three identical alpha-1(III) chains. Its fibrils are thinner and more pliable than Type I. In structural terms, if Type I is rope, Type III is more like fine cord.

Where they sit in cattle tissue

Both types appear in soft connective tissues, but their proportions shift depending on the tissue's mechanical job. In cattle hide — the primary source for bovine collagen supplements — Type I dominates, typically accounting for around 80–90% of total collagen content. Type III is present alongside it, particularly in the more pliable dermal layers. The two are not segregated into separate compartments; they co-polymerise, meaning Type I and Type III fibrils interweave in the same structural matrix.

This co-polymerisation is the reason you cannot simply extract one without the other from hide. Separating them would require processes that defeat the purpose of producing a food-grade hydrolysate. So when a bovine collagen product lists both types, it is describing the biology of the source material, not an engineered blend.

Why hide and not another tissue?

Cattle provide several collagen-rich tissues — hide, bone, tendon, cartilage. Cartilage is dominated by Type II collagen, which is structurally different again and predominantly found in that tissue. Bone yields mostly Type I. Hide gives the most consistent Type I and III combination at scale, which is why it became the standard source for supplement-grade bovine collagen.

It is worth being clear about what the type designation does and does not tell you. It describes molecular structure and tissue origin. It does not, on its own, tell you how well a product is hydrolysed, what peptide sizes it contains, or how it will behave in solution. For that, you need to look at the label more carefully — the guide to what to look for in a bovine collagen powder covers those details.

Hydrolysis and what happens to the types after processing

Raw collagen from hide is not digestible in any useful sense — the triple helix is too stable and too large. Hydrolysis breaks it down into shorter peptide chains, typically ranging from around 2,000 to 5,000 daltons, though the precise range varies by manufacturer and process. At that point the triple helix no longer exists as a structure; what remains are fragments of the original chains.

So when a label says hydrolysed Type I and III, it means the source material contained those types before hydrolysis. The peptides themselves are chain fragments, not intact collagen molecules. This matters for setting expectations about the product, not for doubting its quality — hydrolysis is exactly what makes bovine collagen soluble and usable as a supplement.

Type I and III versus Type II

You may also see Type II collagen on the market, usually sourced from chicken sternum or bovine cartilage. It is a different molecule with a different tissue distribution. It is not interchangeable with Type I and III, and the sources do not overlap in any practical sense. Bovine hide does not yield meaningful Type II; cartilage does not yield meaningful Type I. If you are specifically looking into Type II, that is a different product category entirely.

The marine comparison

Marine collagen — from fish skin and scales — is Type I only. If that distinction is relevant to your decision, the comparison between the two sources is worth reading separately. The bovine versus marine collagen page goes into that in more detail. Please note: marine collagen contains fish and is not suitable for anyone with a fish or shellfish allergy or intolerance.

Pump House's Pure Bovine Collagen Powder provides 10,000mg of hydrolysed Type I and III peptides per 10g serving, sourced from the hides of grass-fed, pasture-raised EU cattle. If you prefer a capsule format, the Collagen 400mg Capsules use the same hydrolysed bovine source. Both are unflavoured and single-ingredient.

There is no authorised health claim in GB for collagen supplements of any type. The research landscape is active: a 2025 meta-analysis pooling 23 randomised controlled trials found significant effects overall on certain measured outcomes, but subgroup analyses — particularly those limited to higher-quality or independently funded trials — showed no significant effect. That split means the evidence remains genuinely contested, and no firm conclusions can be drawn. What Type I and III tells you is where the protein came from and how it is structured at source. That is a useful label reading, even if it is not the whole story.