Stretch marks, also known as striae, are an otherwise harmless form of scarring caused by the stretching of the skin during pregnancy, weight gain or bodybuilding. Stretch marks can form on any part of the body, but they mostly affect high-fat areas like the abdomen, breasts, buttocks and thighs. Stretch marks can appear as thin, wavy lines with a red, purple, or white complexion. Oftentimes, stretch marks will not diminish by themselves and can last for many years or a lifetime. Fortunately, there are dermatologically-advanced ways to help fade stretch marks and affordable products are readily available online.