Even with the best sunscreen, wrinkles cannot be totally avoided. Some wrinkling is inherited, and a certain amount is caused by age. Aside from avoiding UV damage, some practices might prematurely age skin. For example, smokers and people who use tanning beds often have wrinkled skin. Even if you don't smoke or tan, you may still inherit certain genes that lead to premature aging of the skin. The three main factors that influence the appearance of wrinkles are age, sun exposure, and genetics. Other factors include gender, smoking, alcohol consumption, and poor nutrition/obesity. As we get older, our skin changes, including becoming less responsive to growth factors such as insulin and estrogen. This reduces the ability of skin to repair itself after injury, which leads to scarring and more frequent need for cosmetic procedures such as facial injections and surgery. Sunlight causes damage to the skin by causing inflammation and creating free radicals, which are particles that contain an electron missing from its parent atom. These particles can then interact with other molecules, removing their electrons in the process. This can cause serious problems for cells because they cannot function without these electrons. Over time, this will cause damage to DNA and lead to wrinkles. Genetics also play a role in determining how quickly we age.