They are great for moisturizing the skin, but there's no way that being wrapped in plastic or herbal potions can cause fat loss. If they could there wouldn't be a fat person alive! As to stretch marks, these are literally scars that form when the underlying skins structures "split" due to rapid expansion. There has been some success with lasers, and prescription drugs, in reducing their appearance, but again a "body wrap" cannot really do much for them. Any weight loss is caused by dehydration due to sweating, and is temporary as the water balance will rapidly be restored upon consuming fluids.