Collagen Types I II III: What Are the Differences and Which Collagen to Choose

When you write "collagen" on a supplement label, what exactly do you mean? Scientists have identified at least 28 types of collagen in the human body so far. Three of them – types I, II, and III – account for over 90% of the total collagen pool in the body. Each serves different structural and biological functions, each dominates in different tissues, and each is the right choice for different health issues. Are you taking collagen for joints? You might be taking the wrong type. For skin? It may be lacking in your supplement. This article explains how collagen types actually differ and how to tailor supplementation to your goal.

KEY INFORMATION
• Collagen type I makes up about 75% of the total collagen mass in the body – present in the skin, bones, and tendons; the most widely studied in supplementation (Proksch et al., 2014).
• Collagen type II dominates in articular cartilage; undenatured type II (UC-II, 40 mg) works through immune tolerance – a different mechanism than types I and III.
• Collagen type III coexists with type I in the skin and blood vessels; its ratio to type I changes with age, affecting skin elasticity.
• Bovine hydrolysate contains types I + III; fish hydrolysate contains only type I; chicken cartilage contains type II.

Collagen Type I – What Does It Do and Who Is It Suitable For?

Collagen type I is by far the most common collagen in the body – it accounts for about 75% of the total collagen pool and dominates in the dermis, cortical bones, tendons, cornea, umbilical cord, and teeth. Its primary function is mechanical strength under tension: collagen type I fibers have one of the highest Young's modulus values among biological materials – comparable to steel at the same weight. For this reason, a deficiency of collagen type I translates to brittle nails, weak tendons, and more pronounced wrinkles.

In the skin, collagen type I forms a dense network in the reticular layer of the dermis, providing elasticity, tension, and resistance to mechanical damage. The natural decline in collagen type I production in the skin (about 1% per year after the age of 25) results in visible wrinkles and decreased skin turgor. Proksch et al. (Skin Pharmacology and Physiology, 2014) They demonstrated in a double-blind RCT that supplementation with 2.5 g of collagen hydrolysate (type I) for 8 weeks improves skin elasticity by 15% compared to placebo – the effect persisted for 4 weeks after the treatment ended, suggesting a lasting stimulation of fibroblasts, not just a temporary "filling" with substance.

Collagen type I is also crucial for bone health: it constitutes the organic matrix of cortical bones, on which hydroxyapatite (the mineral component of bones) is deposited. Deficiencies in collagen type I (e.g., in osteogenesis imperfecta) lead to bone fragility even with normal calcium levels. Supplementation with collagen type I in postmenopausal women – a group at high risk for osteoporosis – showed in a study by König et al. (Nutrients, 2018) a reduction in bone degradation markers at a dose of 5 g daily for 12 months.

Collagen Type II – The Best for Joints?

Collagen type II is the dominant structural component of articular cartilage (60–80% of the dry mass of cartilage) and the vitreous body of the eye. Unlike collagen type I, which forms thick tensile fibers, type II creates a thin network of fibers resistant to compression – which perfectly matches the function of cartilage as a joint cushion.

Supplementation with collagen type II is more complex than it seems at first glance. There are two mechanisms. The first: hydrolyzed collagen type II – digested into peptides that stimulate chondrocytes (cartilage cells) to synthesize proteoglycans and new collagen type II. Dose: 10 g/day, similar to type I. The second: undenatured collagen type II (UC-II) – a special form with a standardized triple helix structure. UC-II at a dose of just 40 mg per day induces immunological tolerance in MALT tissue in the intestine – the immune system "learns" not to attack articular cartilage (a mechanism important in rheumatoid arthritis and degenerative disease). Lugo et al. (JISSN, 2016) demonstrated the superiority of UC-II over a combination of glucosamine + chondroitin in a 6-month RCT.

Collagen Type III – An Underrated Component of Healthy Skin and Blood Vessels

Collagen type III often goes unnoticed because it is less frequently mentioned on supplement labels. Meanwhile, it is crucial for skin elasticity, especially at a young age. In the skin of a newborn, type III can account for up to 50% of the total collagen – with age, its proportion decreases, and type I dominates. This ratio matters: skin rich in type III is soft, elastic, and resilient; skin with low type III is tougher and less elastic.

Besides skin, type III builds the walls of blood vessels (mainly venous), heart, lungs, intestines, and spleen. Mutations in the type III collagen gene (COL3A1) cause Ehlers-Danlos syndrome type IV – a genetic disease characterized by the fragility of blood vessels and intestines, illustrating how important its structural role is. Supplementing with grass-fed bovine collagen provides both type I and type III – this is an important advantage over marine collagen (type I only). Type III is not available as a separate supplement – it always occurs together with type I in bovine hydrolysate in a ratio of about 4:1 to 6:1 (I:III). Therefore, when choosing a product, you do not need to look for a separate "type III supplement" – regular bovine hydrolysate contains it.

How to choose the right type of collagen for your issue?

Choosing the type of collagen should start with a clear definition of the goal. Below is a practical guide for selection.

Goal: improving skin appearance (wrinkles, elasticity, hydration) → Type I collagen (possibly type I + III from bovine hydrolysate). Dose: 2.5–5 g daily for a minimum of 8 weeks. Products: fish hydrolysate (type I, higher bioavailability) or premium bovine hydrolysate (type I + III, cheaper). Vitamin C is mandatory.

Goal: reducing joint pain, osteoarthritis → Type II collagen. Option 1: UC-II (und denatured type II), 40 mg/day for 6 months. Option 2: hydrolyzed type II, 10 g/day. UC-II is more effective for joints according to Lugo et al. (2016). It can be combined with omega-3 fatty acids for anti-inflammatory synergy.

Goal: bone health, osteoporosis prevention → Type I collagen, 5–10 g/day. Mandatory: vitamin D3 + K2 for proper calcium incorporation. We discuss the synergy of D3 and K2 in the article Vitamin D3 and K2 – why combine them.

Goal: comprehensive supplementation (skin + joints + vessels) → Bovine hydrolysate (type I + III), 10 g/day + separately UC-II 40 mg for joints. This combination addresses all three types without the risk of interactions.

Our observations: Many "collagen for joints" preparations contain bovine hydrolysate (type I + III), marketed as "joint collagen". This is not a mistake – type I stimulates fibroblasts and may indirectly improve the condition of cartilage – but expecting a specific joint effect from type I without type II or UC-II is unjustified. If you are looking for a supplement for joint pain, check the label to see if it contains UC-II or type II collagen (not just type I).

Frequently Asked Questions

What is the difference between type I and type II collagen?

Type I (75% of the total) dominates in skin, bones, and tendons – responsible for mechanical strength. Type II dominates in articular cartilage – responsible for resistance to compression. Proksch et al. (2014) studied type I for skin; Lugo et al. (2016) – UC-II (und denatured type II) for joints.

What is type III collagen used for?

Type III collagen builds the elastic layer of the skin (reticular), blood vessel walls, intestines, and heart. It is particularly important in youth – its ratio to type I decreases with age. Bovine hydrolysate provides type I + III together; marine – only type I.

What dose of type II collagen is effective for joints?

UC-II (und denatured type II) – 40 mg daily. Lugo et al. (JISSN, 2016) demonstrated the superiority of 40 mg UC-II over 1500 mg glucosamine + 1200 mg chondroitin over 6 months. Hydrolyzed type II collagen – 10 g daily (similar to type I).

Can type I, II, and III collagen be combined together?

Yes – there are no interactions. Type I + III naturally co-occur in bovine hydrolysate. UC-II works through a different mechanism (intestinal, immunological) and can be supplemented simultaneously with type I + III for comprehensive support of skin and joints.

Where does type II collagen for supplements come from?

Mainly from chicken sternal cartilage. UC-II is a patented extract from chicken cartilage, standardized to 40% und denatured type II collagen. It can also come from bovine cartilage – the difference is in the degree of denaturation, not in the biological source.

This article is for informational and educational purposes and does not replace consultation with a doctor. If you are pregnant, breastfeeding, taking medications, or have chronic conditions, consult the use of supplements or herbs with a specialist.

Author: Michał Waluk · Published: 2026-05-04 · Updated: 2026-05-04