There are about 28 types of collagen in the human body, but for skin, hair and supplements only a handful matter: type I, which makes up roughly 90 percent of your collagen, type III, which sits beside it in skin, and type II, which belongs to cartilage. Everything else is either specialised or rarely sold.
Labels add confusion by listing types like a menu. This guide tells you what each type is, where it comes from in a tub, and why the type number is less useful than the label suggests once collagen has been digested.
At a glance
How many types
About 28 are known. Types I, II, III, IV and V do most of the work.For skin
Type I and type III, usually from bovine or marine sources.For joints
Type II from chicken cartilage. Undenatured type II is a separate product taken at about 40 milligrams.Do types matter once eaten
Less than labels suggest. Hydrolyzed collagen is digested into amino acids and short peptides whatever the type.Multi collagen
Blends several types. No good evidence that mixing types helps skin more.
The five types of collagen that matter most
Scientists number collagen types in the order they were discovered, using Roman numerals. So type I is simply the first one found, which also happens to be the most common. Labels often swap the numerals for ordinary numbers, so type 1 and type I are the same thing.
| Type | Where in your body | Common supplement source | Main interest |
|---|---|---|---|
| I | Skin, bone, tendon, ligaments | Cow hide; fish skin or scales | Skin firmness and hydration |
| II | Cartilage | Chicken sternum cartilage | Joints |
| III | Skin, muscle, blood vessels, organs | Cow hide (alongside type I) | Skin, often sold paired with type I |
| IV | Basement membrane under the skin surface | Not usually sold | Anchors skin layers |
| V | Cornea, hair, parts of the skin | Small amounts in some blends, eggshell membrane | Helps form other fibers |
To learn how these molecules are built in the first place, read our explainer on what collagen is.
Type 1 collagen: the skin and bone type
Type I is the workhorse. It forms thick, strong fibers that run through the dermis, bones, tendons and ligaments. When people talk about losing collagen in the face, they mostly mean type I.
A type 1 collagen supplement is almost always hydrolyzed collagen from cow hide or fish. Marine collagen is mostly type I. Bovine collagen is type I with some type III. If you see "collagen peptide type 1" on a label, it means peptides made from type I rich raw material.
- Who it suits: people whose goal is skin hydration and elasticity.
- Typical amounts in skin trials: a low of 2.5 g and a high of 10 g daily.
- Where to compare sources: our marine versus bovine comparison.
Type 2 collagen: two very different products
Type II collagen is the main protein in cartilage, the rubbery cushion at the ends of bones. Supplements made from it come in two forms, and mixing them up is the most common mistake people make with collagen types.
| Feature | Hydrolyzed type II | Undenatured type II |
|---|---|---|
| Processing | Broken into peptides, like other collagen powders | Kept in its native shape with low heat |
| Typical amount | Grams | About 40 milligrams |
| Usual form | Powder or capsule | Small capsule |
| Main claim | Joint comfort | Joint comfort through a gut immune effect |
| A skin product? | No | No |
Undenatured type 2 collagen is taken in tiny doses because the theory is that it trains the immune system in the gut, not that it supplies building material. Evidence is limited and comes from a small number of trials. Either way, type 2 collagen benefits, if any, are about joints, not wrinkles.
Type 3 collagen and why it is sold with type 1
Type III forms finer, more flexible fibers than type I. In skin, the two are woven together. Young skin and freshly healing wounds have a higher share of type III; as skin matures, type I takes over.
You rarely see a pure type III supplement. Instead, "collagen type 1 and 3" on a label almost always means bovine collagen, because cow hide naturally contains both. So the type 1 and 3 collagen benefits are the same as those of bovine collagen in general: modest support for skin hydration and elasticity in small trials. Our bovine collagen guide goes deeper.
Type 4, type 5 and the other 20 or so
The remaining types are real and important, but you will not shop for them.
- Type IV forms sheets rather than ropes. It builds the basement membrane, a thin layer that glues the epidermis to the dermis and wraps blood vessels and kidney filters.
- Type V appears in the cornea, hair and some layers of skin. It helps control how thick type I fibers grow. Some blends list it, often from eggshell membrane.
- Type X is involved in bone growth plates. A few blends list it, with no skin evidence.
- Others are found in specific places such as the anchoring fibrils under the skin or around muscle cells.
A long list of types on a label looks impressive, but it does not mean the product does more. It mainly tells you the product mixes several raw materials.
Do the different types of collagen matter once you swallow them?
This is the question most labels skip. Hydrolyzed collagen is digested in the gut into single amino acids and short chains of two or three amino acids. Those small pieces no longer carry a type number. Your body then builds its own collagen, of whatever type each tissue needs.
That is why the source and the grams per serving tell you more than the type. A few short peptides, such as one made of proline and hydroxyproline, do reach the blood and may act as signals to skin cells. They come from most collagen sources, not one type in particular.
The one real exception is undenatured type II, which is designed not to be broken down. It is a joint product, as explained above.
Choosing between the types of collagen supplements
Use this if this, then that table instead of the type number printed on the label.
| If your goal is | Then look for | Why |
|---|---|---|
| Skin hydration and firmness | Hydrolyzed type I, or I with III, at trial level doses | Matches the form used in skin trials |
| Joint comfort | Type II, either hydrolyzed or undenatured | Matches the form used in joint trials |
| Avoiding beef or pork | Marine type I | Fish source, but not for fish allergy |
| One product for everything | Be wary of multi collagen claims | No good proof that blends beat a single source |
| Hair and nails | Any hydrolyzed type, with modest hopes | Evidence is thin for all types |
Whatever you pick, check how many grams each serving holds and look for a third party testing seal. You can compare blends on our multi collagen page, and see what to expect for your face on collagen for skin. For the hair question, read collagen for hair.
Questions people ask
What is the best type of collagen for skin?
Type I, often paired with type III, is the type found in skin and the one used in most skin trials. In practice that means a hydrolyzed bovine or marine collagen. The daily grams matter more than the exact type.
What is type 2 collagen used for?
Type II comes from cartilage and is sold for joint comfort, not skin. Undenatured type II is taken at about 40 milligrams a day, a very different dose from skin collagen. Evidence for joints is limited, so it is worth discussing with a doctor.
Type 1 vs type 2 collagen: can I take both?
Yes, there is no known problem with taking a type I powder and a type II capsule together. They just have different goals, skin for one and joints for the other. Check total protein intake and any allergy to the source.
What is type 3 collagen?
Type III is a finer, more flexible collagen found in skin, blood vessels, muscle and organs, usually woven with type I. In supplements it nearly always comes from cow hide, sold as type 1 and 3. It is not usually sold alone.
Is a collagen type 1 2 3 blend better?
Not as far as current research shows. Once hydrolyzed collagen is digested the type number is largely lost, and no good trials show that mixing types works better for skin. A blend may simply give you a longer label rather than better skin.