Collagen – Properties, Types, Sources and Applications

Collagens constitute a category of fibrous proteins that serve as the predominant constituents of the extracellular matrix within animal organisms. These proteins are indispensable components of most connective tissues, including osseous structures, cartilaginous material, epidermal layers, and ligamentous systems. Their primary biological role involves maintaining the mechanical resilience of tissues, preserving their elastic configuration, and conferring resistance to external tensile forces. Furthermore, collagens play an active part in restorative processes by facilitating the repair of damaged tissues and accelerating wound closure, thereby contributing to the preservation of skin firmness, suppleness, and a smooth surface texture.

So far, 29 different forms of collagen have been identified in the human body for different functions, including eight main groups with different roles and locations, including: type I, which makes up as much as 90 percent of the body's collagen proteins, found in the skin, bones, tendons, ligaments and corneas of the eye, type II in the cartilage of the joints, type III in the vessel-building, uterine walls and intestines, type V, type XI in the bones, skin and ligaments, type XXIV and type XXVII in the excretion of the cornea and particles.

From a nutritional standpoint, collagen is classified as a biologically incomplete protein due to its deficiency in certain essential exogenous amino acids. Its proper biosynthesis within the human body is critically dependent on an adequate supply of vitamin C, the deficiency of which may disrupt this vital metabolic pathway. The richest dietary sources of collagen are found in animal-derived products, including broths made from chicken feet (such as homemade aspics), pork knuckles, poultry cartilage, and skin. Furthermore, animal collagen serves as the primary raw material for the production of edible gelatin. A progressive decline in collagen levels is associated with deterioration in skin and nail integrity, impaired circulatory and lymphatic system functionality, and may contribute to the development of degenerative joint diseases as well as accelerated somatic cell aging.

Collagen, frequently referred to as the "protein of youth," serves a pivotal function in both aesthetic medical procedures—where it is employed to correct wrinkles, volume deficiencies, or scars—and as a key ingredient in numerous skincare formulations, including gels, serums, and creams. It is critical to emphasize, however, that topically applied collagen (e.g., in cream form) cannot penetrate the deeper layers of the skin due to its excessively large molecular size, which prevents translocation across the epidermal barrier. Nevertheless, it exerts a potent hydrating effect that indirectly contributes to the smoothing of fine facial lines and enhances skin suppleness. Far greater benefits are derived from oral supplementation with hydrolyzed collagen, which acts systemically: it promotes the regeneration of connective tissue—including articular cartilage—counters the loss of dermal density, and reinforces the structural integrity of the skin. Consistent intake of this protein (through an amino acid-rich diet or collagen supplements) may decelerate aging processes, fortify joint health, and reduce the likelihood of degenerative changes. Complementary to this, integrating at-home skincare routines—such as hydrating or antioxidant masks—can amplify rejuvenating outcomes. Proactive maintenance of optimal collagen levels should commence well before the age of 25, as adequate provision not only sustains a youthful complexion but also ensures the long-term functionality of the musculoskeletal system.