Type I collagen is a major protein in animals, and its hydrolyzed products, collagen peptides, have wide-ranging applications. This article reviews collagen peptides’ preparation methods, biological activities, and application progress in the fields of food, cosmetics, and medicine. By employing various extraction and hydrolysis methods, collagen peptides with different molecular weights can be obtained, and their biological activities are closely related to their molecular weight and amino acid sequence. Studies have revealed that collagen peptides possess a variety of biological activities, including antioxidant, hematopoietic promotion, osteogenic differentiation promotion, antihypertensive, and anti-diabetic effects. In the food industry, their antioxidant and hypoglycemic properties have opened new avenues for the development of healthy foods; in the cosmetics field, the moisturizing, anti-aging, and repair functions of collagen peptides are favored by consumers; in the medical field, collagen peptides are used in wound dressings, drug carriers, and tissue engineering scaffolds. Looking to the future, the development of green and efficient preparation technologies for collagen peptides and in-depth research into the relationship between their structure and function will be important research directions. The multifunctional properties of collagen peptides provide a broad prospect for their further application in the health industry.

An antibacterial, injectable, thermosensitive, and physically cross-linked hemostatic hydrogel was prepared based on quaternized linetype poly(N-isopropylacrylamide), hyaluronic acid and gelatin.