Collagen is the most abundant protein in the body; the structural protein is a significant component of cartilage, skin and connective tissue. There are up to 29 different collagen types, each with slightly different roles and functions in the human body. However, the vast majority of our collagen is either type I, type II or type III collagen so this guide primarily the focuses on these.
Different tissues contain varying proportions of the collagen types, so learning how to identify each form of collagen and their sources helps you make better, goal-oriented choices.
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What are the collagen types and their roles?
What is collagen and why are there different types?
Collagen, in its simplest form, is a fibrous protein made up of three amino acids (glycine, proline and hydroxyproline). However, each type has a different structure and mechanical properties. Some of them are great for creating tensile strength – think cables on a suspension bridge. Others are great for absorbing force or forming net-like structures.
There are lots of different benefits of collagen, such as joint support, wound healing and the maintenance of bone density. The variety of different collagen types makes gives rise to amy potential benefits.
The structure and role of types I and III collagen
Type I is the most abundant type of collagen, accounting for 90% of the body’s total collagen. It is extremely strong and makes up a large proportion of our bone density, skin, ligaments and tendons. Type I collagen is like a rope, it has a tight triple helix structure made up of alpha 1 and alpha 2 collagen. These helices bundle together to form protein fibrils and then collagen fibres.
Type I collagen fibres are extremely strong, highly resistant to stretching and help prevent tears in our skin or ligaments, for example. A decline in collagen levels can contribute to skin laxity, fine lines and even joint pain.
Type III collagen represents about 5-20% of the body’s collagen structures and has a more flexible net-like structure. It also features a similar triple helix, but instead of forming straight cables, it branches out, creating a mesh. Its structure allows for expansion, recoil and stretching unlike type I. Type III collagen is predominantly found in flexible tissues such as the skin, blood vessels and the lungs.
The interesting thing about types I and III collagen is that they work together. Type III is laid down first, and then as tissue matures, type I collagen replaces and builds over it. This is partly why younger skin and connective tissue are more supple than adult skin. It’s not all to do with a decline in collagen levels.
Feature |
Type I |
Type III |
|---|---|---|
Fibril thickness |
Thick |
Thin |
Organisation |
Parallel bundles |
Branching mesh |
Strength |
Very high |
Moderate |
Elasticity |
Low |
High |
Tissue age |
Mature |
Young / healing |
Main job |
Tensile strength |
Flexible support |
The structure and role of type II collagen
Where types I and III collagen function by resisting pulling strength, type II collagen functions by resisting compression, and absorbing force. This is why areas like our spinal discs, knees and ankles are rich in type II collagen. Type II collagen has a very specific function, so it makes up 60-95% of the collagen found in articular cartilage; however, it only makes up 1-5% of the body’s total collagen.
The collagen type II structure is also a triple helix but utilises only alpha 1 collagen. It forms thin fibres instead of dense rope-like structures. These fibres form a dense, interwoven network. Type I collagen is like rope or string, whereas type II collagen is reminiscent of wool or felt.
Other types of collagen explained
There are so many other types of collagen that, together, make up less than 1% of the total. These have various functions from filtration, anchorage, connection, organising, stabilising and more. Other types of collagen may help with hair loss, dry skin or gut filtration concerns (leaky gut).
Comparing collagen types and collagen sources
The terms collagen types and collagen sources are often used interchangeably. A collagen source is usually the animal from which collagen was extracted, such as marine or bovine collagen. However, the type of collagen refers to its biological structure. Different sources of collagen can have varying proportions of each collagen type, so it is worth considering which one you want to prioritise in your diet.
● Bovine collagen: usually extracted from the bones (with less cartilage) so it is rich in type I collagen.
● Marine collagen: usually extracted from fish skin which is rich in type I and type III collagen.
● Chicken collagen: usually extracted from the whole carcass, and feet, which are rich in type I and if the skin is included it will also be rich in type III collagen.
● Porcine collagen: Usually dominant in collagen types I and III – very similar makeup to human connective tissue.
● Egg collagen: the membrane of egg shell is rich in type I collagen.
Each collagen source and dietary supplement will contain a variety of different collagen types and reputable supplement brands should list which types they are dominant in.
Choosing a collagen supplement
Which collagen type should you choose?
It is usually best to choose a collagen supplement with more of the type of collagen that you need. For example, if your goal is skin health, choose type I and type III-dominant supplements, whereas if your goal is joint health, ensure yours contains type II. Most supplements will be a mix of different types, so it’s not the be-all and end-all.
Type I and III collagen supplements for skin
For types I and III – ideal for the skin, bones, tendons and vascular system - you’ll want to prioritise bovine or marine collagen. Marine collagen might have slightly more type III than bovine sources so it could be better for skin and vascular health. Read the literature supporting collagen supplementation for skin, and the health benefits of marine collagen.
Our top picks:
- Swedish Nutra Collagen Powder: it lists its collagen types and uses premium bovine sources.
- Vital Proteins Marine Collagen Powder: Marine collagen has a similar make-up to our own skin collagen – mostly type I and III.
Types I and II collagen supplements for joints
If your main priority is supporting the joints, you’ll want a blend of types I, II and III. This is because your joints are made up of cartilage, tendons, ligaments and other structures that rely on a range of collagen types. For this reason, we have selected the Nature’s Plus Collagen Powder because it contains four collagen sources (bovine, marine, chicken and egg) for a complete collagen profile. It also comes in a tasty berry lemonade flavour.
Better yet, the sources are grass-fed, free range or wild-caught, ensuring the highest quality and ethical standards.
Does the type of collagen supplement really matter?
After all this discussion on the best collagen types for different health and beauty goals, does it all make a difference? The answer isn’t simple. The body breaks down collagen into building blocks; most supplements use peptides or collagen hydrolysate, which is already broken down. Ultimately, the body digests dietary protein and decides what to do with the components but without the right building blocks, this can be rate-limiting for collagen production.
There is also some additional nuance. Certain peptides are bioactive, meaning they aren’t just building blocks for collagen synthesis; they communicate with cells. Some peptides from collagen reach tissues where they upregulate collagen-producing cells called fibroblasts. This has a knock-on effect on hyaluronic acid production.
Ultimately, if you’re shopping around for the best collagen supplement, you may want to choose the most appropriate collagen type for your needs, but it’s not essential for getting results.
Frequently asked questions
Which collagen type is best for skin health?
Types I and III are the most common in the skin but the type and the proportions matter less than you think. Instead, choose a quality supplement that delivers effective dosages of collagen peptides (10g or more)
What are the main sources of collagen types I, II, and III?
Marine collagen will contain all three types; chicken collagen will contain mostly type I and II collagen (sometimes type III). Finally, bovine collagen will contain mostly type I collagen.
Do collagen types matter in peptide supplements?
Possibly, but less than you would expect. Collagen is broken down into peptides and amino acids, and the body decides how to use them. You are simply providing the right materials and building blocks with a collagen supplement.
Are certain collagen types better absorbed as supplements than others?
It is a common misconception that marine collagen is better absorbed because it is most similar to our own skin’s collagen. However, in a peptide supplement, the types are virtually the same when it comes to digestion and absorption.
