Collagen Type II

Type II collagen is one of the many forms of collagen in the body and is the defining protein of hyaline cartilage, the smooth tissue that covers the ends of bones in a joint ^[1]. It makes up roughly half of all the protein in cartilage and the large majority of the collagen there, forming a fibrous mesh that traps water-binding molecules and gives cartilage its combination of resilience and tensile strength; it is also a component of the jelly-like vitreous of the eye ^[1]. The protein is produced from the COL2A1 gene, and inherited mutations in that gene cause a range of skeletal and connective-tissue disorders and can predispose to osteoarthritis ^[1].

Type II collagen has attracted attention as a supplement in two very different physical states ^[1][2]. Hydrolyzed collagen, which is broken into small peptides, is used as a general source of collagen amino acids, whereas undenatured type II collagen keeps the protein's natural three-dimensional shape intact ^[1][2]. The undenatured form, commonly sold under the name UC-II and sourced from chicken sternum cartilage, is taken in very small daily amounts, a striking contrast to the much larger servings of collagen peptides, because it is believed to act as a signal to the immune system rather than as a nutrient ^[2][3].

Undenatured type II collagen has been studied mainly in osteoarthritis of the knee. In randomised, double-blind, placebo-controlled trials, a small daily amount reduced pain, stiffness and disability as measured by standard osteoarthritis scores, and in more than one study it outperformed a common combination of glucosamine and chondroitin ^[2][3]. Other work in healthy adults who experience activity-related joint discomfort found that the same supplement improved knee flexibility and range of motion ^[4]. Native type II collagen has also been investigated in rheumatoid arthritis, where the aim is to calm an immune attack on the body's own cartilage ^[1].

The proposed benefits of the undenatured form rest on a process called oral tolerance, in which repeated small exposures to a protein in the gut train the immune system to react less aggressively to it ^[2]. This is a different rationale from that of collagen peptides, and it is why the two products are used at such different amounts ^[2][3]. As a food-derived ingredient, type II collagen supplements are regulated as dietary supplements rather than as medicines, and they are sold as capsules or tablets, sometimes on their own and sometimes combined with other joint ingredients ^[1][2].

In the clinical studies conducted so far, undenatured type II collagen has been well tolerated, with safety outcomes similar to placebo, although the trials are relatively small and often funded by industry, so larger independent research would help confirm the benefits ^[2][3]. It is widely available without prescription ^[1].

Very well tolerated at the small doses used; side effects are rare and mild. There's little concern for healthy people, though anyone with an autoimmune condition should check with a doctor given the immune-modulating mechanism. Sourced from chicken cartilage, so it's not suitable for those with certain allergies.