Bovine vs Marine Collagen: Types I, II and III Explained

If you've shopped for collagen, you've seen the claims: marine absorbs better, type I is all you need, bovine is old news. Maybe you're choosing your first collagen, or wondering whether the one you've been taking is the right one. Here's what the research actually shows, in plain language, so you can choose with confidence.

Jump to: Types I, II and III · Bovine vs marine · Bioavailability · Which suits you · How much · FAQ

What is collagen?

Collagen is the main structural protein in your body, making up around 25 to 30% of all your body's protein. [2] It's the scaffolding in your skin, bones, tendons, ligaments, cartilage and blood vessels.

Your body makes at least 28 types of collagen, but three do most of the work, and they're the ones you'll see on supplement labels. [2]

Types I, II and III

The three types on the label

Where each collagen works

I and III work as a team

IType

Skin, bones, tendons and ligaments

Gives tissues their strength. Over 90% of your body's collagen.

Comes from: Bovine hide, fish skin

IIType

Cartilage in your joints

The cushioning that absorbs impact.

Comes from: Cartilage

IIIType

Skin and blood vessels, alongside type I

Adds flexibility to tissues.

Comes from: Bovine hide, together with type I

See the full numbers

Type	Where it's found	What it does	Where supplements get it
Type I	Skin, bones, tendons and ligaments. Over 90% of your body's collagen [3]	Gives tissues their strength	Bovine hide, fish skin
Type II	Cartilage, the cushioning in your joints [3]	Absorbs impact in joints	Cartilage
Type III	Skin and blood vessels, alongside type I [2]	Adds flexibility to tissues	Bovine hide, together with type I

Types I and III work as a team: type I brings tensile strength and type III brings flexibility. [2] That's why getting both together matters.

Bovine vs marine at a glance

Hydrolysed collagen, side by side

Bovine vs marine

Bovine

More complete

From cattle

Type IType III+ II in some blends

Suitable with a fish allergy

Marine

From fish skin and scales

Type IType III

Not suitable with a fish allergy

=Absorbed equally well. A 2024 study comparing hydrolysed fish, pork and bovine collagen found comparable uptake from every source.

See the full numbers

	Bovine collagen	Marine collagen
Comes from	Cattle	Fish skin and scales
Collagen types	Types I and III, plus type II in some blends	Essentially type I only
Absorption	Well absorbed when hydrolysed [1]	Well absorbed when hydrolysed [1]
Fish allergy	Suitable	Not suitable
Suitable for vegans	No	No

Bioavailability: what actually matters

How well collagen is absorbed comes down to how it's processed, not which animal it came from.

Whole collagen is a large, tightly wound protein. Hydrolysing breaks it down into small peptides your body can absorb easily. Some of those peptides, short chains of two or three amino acids such as proline-hydroxyproline, are absorbed intact and are the fragments linked to collagen's benefits. [1]

A 2024 crossover study tested hydrolysed collagen from fish, pork and cattle, including bovine collagen at two different peptide sizes. [1]

• All sources produced comparable uptake of hydroxyproline, the amino acid unique to collagen.
• A good share was absorbed as intact di- and tripeptides, from every source.
• The researchers concluded that, regardless of source or peptide size, all the collagen tested reached meaningful levels in the blood.

What about "marine absorbs 1.5 times better"?

It's a popular claim, usually based on marine peptides being smaller. But when researchers compared the sources head to head in people, absorption was comparable. [1] Once collagen is hydrolysed, the source makes little difference to how well you absorb it.

Why hydrolysed bovine collagen is the more complete choice

• More types in every scoop. Bovine hide naturally gives you types I and III together, the same pairing your skin, tendons and ligaments are built from. [2] Marine gives you one.
• Absorbs just as well. Bovine peptides are absorbed as well as fish peptides. [1]
• Suitable with a fish allergy. Marine collagen isn't.
• Easy to use. Hydrolysed bovine collagen dissolves easily in hot or cold drinks.

What collagen supports

Research on hydrolysed collagen supports a wide range of benefits:

• Muscle and strength alongside training. Men over 65 taking 15 g a day with 12 weeks of resistance training gained an average of 4.2 kg of fat-free mass, compared with 2.9 kg on placebo. [5]
• Skin. Across controlled trials, collagen supported better skin hydration and elasticity and reduced wrinkles compared with placebo. [4]
• Joint comfort for active people. In 97 athletes, 10 g a day for 24 weeks supported less joint pain when walking, standing and lifting. [6]

For the full picture, read our collagen vs whey guide and collagen for skin and joints.

How much should you take?

Which suits you?

Get more from collagen: pair it with whey

Collagen specialises in connective tissue. Whey brings leucine and the full set of essential amino acids for building muscle. Together, they support the muscle you're building and the connective tissue that holds it all together. Read why in collagen vs whey.

Our picks

Inception Labs Collagen Whey Protein. NZ whey protein concentrate from grass-fed cows with NZ bovine collagen types I, II and III, giving you up to 27 g of protein per scoop. [7] Supports muscle recovery, your daily protein intake and connective tissue in one scoop.