Collagen type II is a major component of cartilage, the connective tissue that provides structural support to joints. Its use as a dietary supplement is primarily justified by scientific evidence rather than tradition. Several clinical studies and preclinical research support the role of oral collagen II in supporting the structural system, particularly joint health. Hydrolyzed collagen II is thought to stimulate the synthesis of extracellular matrix components and cartilage repair. Randomized controlled trials have shown that supplementation with undenatured type II collagen can reduce joint discomfort and improve mobility in individuals with osteoarthritis and rheumatoid arthritis, likely through immune modulation and cartilage support (Crowley et al., 2009; Bagchi et al., 2002). Mechanistically, collagen II delivers peptides that may act as building blocks for cartilage, and also appears to help regulate immune responses that would otherwise contribute to cartilage degradation. While more large-scale studies are needed, existing evidence supports the use of collagen II supplements for maintaining joint integrity and supporting the structural system, especially in populations at risk for joint degeneration.