The visible effect of aging is evident where it first starts – the skin’s outermost dermis layer, also known as the stratum corneum. Along with wrinkles and fine lines, saggy skin is an age-related concern on many people’s minds. This loss of definition can happen almost anywhere on the body, but the most common areas are the face, neck, abdomen, and arms. Sagging skin is caused by several factors, including thinning of the epidermis (the surface of the skin) and collagen loss. As you get older, the body loses collagen naturally. By extension, this includes elastin, another protein responsible for keeping the skin firm and tight.