What causes wrinkles?
There are many factors that contribute to the onset of wrinkles. The following are the most important:
Wrinkles are a natural by-product of the aging process. With age, skin cells divide more slowly. The inner layer of the skin, called the dermis, begins to thin. The network of elastin and collagen fibers, which support the outer layer, loosens and unravels. This process results in depressions on the skin surface. With aging, skin becomes more fragile. Also, oil-secreting glands are less efficient, making the skin less able to retain moisture and appear more wrinkled. All of these factors contribute to the development of wrinkles.
Facial muscle contractions
Lines between the eyebrows (“eleven” or frown lines) and lines coming out from the corner of the eyes (crow's feet) are believed to develop because of the underlying muscle contractions. Smiling, frowning, squinting, and other habitual facial expressions cause these wrinkles to become more prominent with age. Over time the expressions, along with gravity and the loss of underlying bone and fat mass, contribute to the formation of jowls and drooping eyelids.
Excessive exposure to ultraviolet radiation (too much sun) can result in premature aging of the skin, also known as photoaging. The ultraviolet sunrays that cause photoaging damage collagen fibers (the major structural proteins in the skin) and elastin fibers (the protein that enable skin to stretch). Both of these fibers are important components of the skin’s connective tissue. Without them, the skin loses its strength and flexibility, leading to wrinkles. When ultraviolet light damages skin tissue, certain enzymes are produced. These enzymes create and reform collagen. During the process, however, some healthy collagen fibers are damaged, resulting in a disorganized formation of fibers called solar scars. Wrinkles develop when this rebuilding process occurs over and over.
Healthy skin always regenerates. While old collagen is broken down and removed, new collagen is being produced and installed. Researchers have found that smoking tobacco products causes a reduction in the production of new collagen. A lack of new collagen results in the development of wrinkles. This may also be due to the lack of blood supply to the skin caused by smoking.