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Elegancka kompozycja z pojemnikiem kolagenu w proszku obok zielonych liści i białych kwiatówsenanur ulusoy / Pexels
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Which Collagen Should You Choose? Type I, II and III — What the Research Actually Says

Collagen is one of the most commonly bought supplements in Poland, yet few people know that 'collagen' isn't a single substance — it's a family of proteins with different uses. We explain the difference and help you pick the right type.

AKdr Anna KowalczykAugust 18, 202610 min read
Table of contents

TL;DR — key takeaways

Collagen isn't one substance — it's a family of proteins

More than a dozen types of collagen have been identified in the human body, but in the context of supplementation, mainly three matter: type I (skin, bones, tendons), type II (joint cartilage), and type III (skin, blood vessels, often occurring alongside type I). Which type — or blend of types — a given supplement contains has a direct bearing on what you can realistically expect from it, and the labels on many popular products deliberately don't make that information easy to find, settling for the generic word 'collagen'.

Below we cover each of the three types separately — because although all three are collagen in the chemical sense, in terms of practical use they're as different from each other as three separate supplements with entirely different purposes.

Hydrolyzed Collagen—Sources and Applications

Moderate evidence

León-López A, Morales-Peñaloza A, Martínez-Juárez VM, et al. · Molecules · 2019

A review of the sources and applications of hydrolyzed collagen, explaining the structural differences between the main types of collagen used in dietary supplements.

View study

Table: which type of collagen for what

Collagen typeMain sourceBest for
Type IFish or bovine skin and boneSkin, nails, hair, bones
Type IICartilage (most often chicken)Joints, joint cartilage
Type IIIBovine skin (co-occurs with type I)Skin elasticity, blood vessels

Collagen types in supplements and their uses

Type I and III: what the research says about skin

The best-documented effect of oral collagen supplementation (mainly types I and III, usually combined in one product) is improved skin hydration and elasticity with regular use over several months — a modest but repeatable effect across several independent placebo-controlled trials. Type I is also the most abundant collagen in the human body (up to 90% of total collagen), present not just in skin but also in bones and tendons, which explains why products 'for skin, hair and nails' are almost always based on it.

A Collagen Supplement Improves Skin Hydration, Elasticity, Roughness, and Density

Moderate evidence

Bolke L, Schlippe G, Gerß J, Voss W · Nutrients · 2019

A randomized placebo-controlled trial showing improved skin hydration, elasticity, and density after 12 weeks of oral collagen supplementation.

View study

Type II: a completely different story — cartilage and joints

Type II collagen differs from types I and III not only in source (most often chicken cartilage, rather than fish or bovine skin) but also in the mechanism being studied — instead of affecting skin hydration, it's meant to supply building material for joint cartilage, and in its undenatured form may modulate the immune system's response to the body's own cartilage tissue. That means a type I/III product bought 'for joints' may simply be mismatched to the goal, no matter how well it works for skin.

24-Week study on the use of collagen hydrolysate as a dietary supplement in athletes with activity-related joint pain

Moderate evidence

Clark KL, Sebastianelli W, Flechsenhar KR, et al. · Current Medical Research and Opinion · 2008

A 24-week study in athletes with activity-related joint pain, showing improved joint comfort after regular supplementation with collagen hydrolysate.

View study

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Myth vs. Fact: does collagen in a cream work the same as oral collagen

Myth

Collagen applied to the skin in a cream penetrates it and works the same way as an oral supplement.

Fact

Collagen molecules are too large to penetrate the epidermal barrier — collagen creams work mainly on the surface, as moisturizers, while oral supplementation supplies building-block amino acids absorbed through the digestive tract, which is an entirely different mechanism.

Checklist: how to read a collagen supplement label

What to look for when buying

  • Check that a specific collagen type (I, II, or III) is listed, not just generic 'collagen'
  • Look for a hydrolyzed form (collagen peptides) — better absorbed than non-hydrolyzed collagen
  • The typical effective dose in studies is 2.5–15 g per day, depending on the goal
  • For joints: make sure it's specifically type II collagen, not a type I/III blend meant for skin

Our editorial recommendation

If your goal is skin — look for type I collagen or a type I/III blend, hydrolyzed, used regularly for at least 8–12 weeks. If your goal is joints — type II collagen, typically at a different, lower dose than skin supplements. Mixing up expectations (collagen 'for everything') is the most common mistake when choosing.

The question 'does collagen work' is poorly framed — you have to ask 'which type of collagen, at what dose, for what specifically', because those are three different questions with three different answers.

Dr. Anna Kowalczyk, VitMode editorial team

Frequently asked questions

In skin studies, effects were usually visible after 8–12 weeks of regular use — collagen doesn't work instantly and requires patience.

Not literally — collagen is an animal protein, but supplements with precursors (vitamin C, amino acids, silicon) that support the body's own collagen production are available and sold as a 'vegan' alternative.

Yes — vitamin C is an essential cofactor in the body's natural collagen synthesis, which is why many products combine both ingredients, a combination with solid biochemical justification.

Sources

AK

dr Anna Kowalczyk

PhD in Molecular Biology (University of Warsaw), 8 years researching cellular aging

Anna studied molecular biology at the University of Warsaw, then spent eight years after her PhD in a lab researching the mechanisms of cellular aging and autophagy. She stumbled into science journalism almost by accident — frustrated by how easily her field's findings get oversimplified in the media, she started a blog explaining the biology of aging in plain language. That blog became the seed of VitMode. Today Anna oversees the entire editorial process, holding every piece to the same rigor her old lab demanded: primary sources, methodology checks, and honesty about the limits of the evidence. Outside work, she's a dedicated boulderer.

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Comments (2)

  • KW

    Kasia W. 2 weeks ago

    Very clearly explained, especially the interactions section — I hadn't seen it laid out this well anywhere else.

  • MT

    Marek T. a month ago

    Are you planning to update this with the newest study from this year? I saw an interesting meta-analysis.