Stretch marks are caused by rapid weight loss or gain or growth spurts, and can be more or less severe depending on genetics and skin laxity. Scars (including normal, hypertrophic, and keloid scars) can be caused by any number of factors, including incisions, trauma, burns and those that are spontaneous. Those who suffer from scars and stretch marks find them embarrassing. Treating these often requires a multi-treatment approach, coupled with the use of medical-grade skincare products, to achieve optimal results.