Collagen Types Explained

Collagen is not a single substance but a family of related structural proteins. Scientists have identified at least 28 distinct types in the human body, each with its own structure and role. For everyday purposes, though, three account for the vast majority of the collagen you have: Types I, II and III. Together these make up the bulk of skin, bone, tendon, cartilage and blood vessels. Understanding the differences between them helps explain why different collagen supplements are sourced and marketed in different ways, and why the source of a product determines which types it provides.

Type I is by far the most abundant collagen in the body, making up roughly 90% of your total collagen. It is the principal structural protein of the dermis - the layer beneath the skin's surface - and is also found in bone, tendon, ligament and the white of the eye. Its tightly packed fibres give tissues tensile strength and resilience. Because Type I dominates the skin, it is the type most relevant to skin-focused research, and it is the predominant type found in marine collagen, which is derived from fish skin and scales.

Type II collagen is the main collagen found in cartilage, the smooth connective tissue that cushions joints. Its structure forms a meshwork that traps water and gives cartilage its ability to absorb load and resist compression. Because of this role, Type II is the type studied in the context of joints and cartilage, and it is often sourced from chicken or other avian cartilage. It is worth restating that joint conditions are medical matters: collagen is a food supplement, not a treatment for arthritis or cartilage disease, and persistent joint pain should be assessed by a healthcare professional.

Type III collagen frequently occurs alongside Type I and supports the structure of skin, blood vessels and internal organs. It is especially abundant in more elastic tissues and in skin, where it works in concert with Type I to maintain the dermal network. Bovine collagen, derived from cattle, typically supplies a mixture of Type I and Type III, which is one reason it is a popular general-purpose source. The two types complement each other in the tissues where suppleness and structure both matter.

The collagen type you get depends on the source. Marine collagen (from fish) is predominantly Type I, which is why it is often chosen for skin-focused routines. Bovine collagen (from cattle) provides Type I and Type III. Porcine collagen (from pigs) is similar to bovine. Chicken-derived collagen is a common source of Type II for cartilage-related products. After extraction, supplement collagen is usually hydrolysed into small peptides for absorption, regardless of type. Knowing the source therefore tells you which types a product mainly supplies, which is useful when matching a supplement to your goal.

For skin, hair and nail routines, Type I (and the Type I/III blends from bovine) is the most relevant, which is why marine and bovine collagen are the common choices. For cartilage-related interest, Type II is the type studied. Whichever you choose, remember that collagen has no authorised health claim; the authorised route for skin is that vitamin C contributes to normal collagen formation for the normal function of skin, which is why collagen is often paired with vitamin C. Collagen is a well-tolerated food supplement to use alongside a balanced diet, and results vary from person to person.