According to several viral videos, chewing gum is a quick way to define your jawline, however, experts say this is not the case. Repeatedly chewing gum will cause the masseter muscles, which are the jaw muscles close to your ears, to get bigger. A person would have to be chewing gum for six to eight hours a day for years to get noticeable results. Even if you do notice a difference it will likely just be at the angles of the jaw where the masseter muscles are located. This muscle is not the only factor that affects the appearance of the jawline. Fat pads in the cheeks, excess skin in the neck and the position of the salivary glands also affect what the jawline looks like. So there’s no guarantee that chewing gum will build muscle in the areas of the face that look the best.