Type II collagen is a protein that is part of the cartilage, bone, and other types of connective tissues in animals and humans. It is the basis for hyaline cartilage, including the articular cartilages at joint surfaces. Type II collagen is formed by homotrimers of collagen, type II, alpha 1 chains, and it makes up 50% of all protein in cartilage and 85–90% of collagen of articular cartilage. Type II collagen is organized into fibrils, which allows the cartilage to entrap the proteoglycan aggregate, as well as providing tensile strength to the tissue.

Type II collagen is used for osteoarthritis and other types of joint and muscle pain. It is thought to work by causing the body to produce chemicals that fight pain and swelling. Most collagen type II found in supplements comes from chicken, and some comes from cows. Oral administration of native type II collagen induces oral tolerance to pathological immune responses and may be useful in arthritis.

Undenatured type II collagen may reduce autoimmunity to the bodys own type II collagen, resulting in less joint inflammation in instances of osteoarthritis and rheumatism. Hydrolyzed type II collagen has been processed with a higher degree of heat, acid, and enzymes, resulting in the breakdown of peptides from larger forms into smaller ones. The hydrolysis of type II collagen seems to result in the breakdown of the most immunologically active peptides, meaning that the effect of hydrolyzed collagen on joints may not act via this mechanism. However, in higher doses, hydrolyzed type II collagen might improve joint pain by supplying the amino acids used to repair the damaged tissue.

Type II collagen is found in high amounts in chicken cartilage and can be synthesized and used in powdered collagen supplements and bone broth supplements. Chicken collagen/type II collagen also inherently features chondroitin sulfate and glucosamine sulfate, which are both popular for supporting healthy joints.