Collagen Injections restore elasticity to the skin and bring back its youthful appearance. Since collagen is a protein naturally found in the skin, bones, cartilage, and tendons of the human body, it starts breaking down after a certain age, causing wrinkles and lifeless skin cells. Collagen Injections can be a great way of replenishing the depleting reserves of collagen in the body to bring back the youthful glow of the skin.