Foods that contain collagen include pig’s feet, chicken claws, fish skin, and beef knuckles. Collagen, an incomplete protein, can promote the skin to lock moisture, provide strength and support for bones, interstitial cells of internal organs and muscle cavities, sclera, etc. It is involved in the composition of skin, tendons, bones and connective tissues of animals. Collagen is mainly distributed in the skin, connective tissue, cartilage and other locations of animals, such as pig’s hooves, chicken claws and fish skin. It should be noted that consuming collagen-rich foods is not an effective way to replenish collagen in the body. Collagen in the body mainly rely on their own synthesis, and collagen in food can not be directly utilized by the body, need to be broken down into amino acids and other substances are used. Collagen for poor quality protein, utilization rate is very low, not as good quality protein (such as lean meat, eggs, milk, etc.).