Collagen makes up one-third of the protein in your body. It is primarily found in the skin and other connective tissue, such as cartilage, bones, tendons, and muscle. It helps to hold the body together, adding structure and strength. Collagen is also what gives your skin its elasticity – which demonstrates how flexible and strong it really is. Further, it plays a major role in in replacing dead skin cells. As we age, our body produces less collagen. For women, menopause often marks the reduction in collagen production. After the age of 60, most people will have a noticeable decline in collagen as the skin ages and wrinkles become more prominent. In cosmetic dermatology, collagen is often used as an injectable filler to plump up the skin, giving a renewed appearance of youthfulness.