collagenHome / Guides / Collagen Basics
Collagen Types I, II and III Explained (Without the Jargon)
Labels love to list collagen “types”. Here is what Types I, II and III really mean and which ones matter for skin, joints and bones.
Collagen is the most abundant protein in your body — roughly a third of all the protein you have. It is the scaffolding that holds skin, bones, tendons and cartilage together. Scientists have identified 28 types, but supplement labels usually mention just a handful.
The three that matter
Type I — the structural workhorse
About 90% of the collagen in your body is Type I. It forms strong fibers in your skin, bones, tendons, ligaments and teeth. Bovine and marine collagen supplements are mostly Type I.
Type II — cartilage
Type II is the main collagen in joint cartilage. Supplements usually get it from chicken sternum cartilage. It comes in two very different forms:
- Hydrolyzed Type II — broken down into peptides, taken in grams, like other collagen powders.
- Undenatured Type II (often sold as UC-II) — kept in its native shape and taken in tiny doses, often around 40 mg. It is thought to work through the immune system in the gut rather than as raw building material.
Type III — Type I’s partner
Type III sits alongside Type I in skin, blood vessels and internal organs. Bovine collagen naturally contains both I and III, which is why you often see “Types I & III” on bovine powders.
What about Types V and X?
“Multi-collagen” blends often list Types I, II, III, V and X by mixing several sources (bovine, marine, chicken, eggshell membrane). There is no good evidence that taking more types gives better results than a quality single-source collagen. Sometimes the extra types are present in very small amounts.
Does the type really matter once you swallow it?
For hydrolyzed collagen, your digestive system breaks the peptides down into amino acids and small fragments, such as the dipeptide prolyl-hydroxyproline, which appear in the blood after a dose. Your body then uses these as raw materials and signals. It does not reassemble “Type I from the supplement” into “Type I in your skin”.
So for powders and capsules taken by the gram:
- Type mostly tells you the source (cow, fish, chicken).
- Dose, consistency and quality matter more than the type list.
For undenatured Type II, the form does matter, because the proposed mechanism depends on the intact structure.
Quick guide
| Your goal | What studies typically used |
|---|---|
| Skin hydration and elasticity | Hydrolyzed Type I (bovine or marine), 2.5–10 g/day |
| Joint comfort | Hydrolyzed collagen ~10 g/day, or undenatured Type II ~40 mg/day |
| Bone support | Specific bovine collagen peptides ~5 g/day (limited research) |
| Hair and nails | Small studies only — evidence is weak |
The takeaway
Don’t be swayed by a long list of types. Pick the form that matches your goal, check the amount per serving and look for third-party testing.
Frequently asked questions
How many types of collagen are there?
Scientists have identified 28 types. Types I, II and III make up most of the collagen in the body and in supplements.
Which collagen type is best?
For skin, hydrolyzed Type I (bovine or marine) is what studies used. For joints, undenatured Type II or hydrolyzed collagen at about 10 g a day.
Do I need a multi-collagen with five types?
No. There is no good evidence that more types on the label give better results.
Browse by type: Type II for joints · marine (Type I) · bovine (Types I & III).
This article is for general information only and is not medical advice. Supplements are not reviewed by the FDA for safety or effectiveness before they are sold. Check with your doctor before starting one, especially if you are pregnant, nursing, have allergies (fish, shellfish, eggs) or take medication. As an Amazon Associate we earn from qualifying purchases.
