No, mewing, or the practice of holding your tongue to the roof of your mouth, is not a proven method to become more attractive.
While proponents of mewing claim it can reshape the jawline and improve facial aesthetics, scientific evidence to support these claims is limited and often anecdotal. The reference provided directly states that it will not reshape your jaw and increase your attractiveness. Focusing on developing genuine social skills, like engaging in conversation, is a far more effective way to become more attractive.
It's important to be critical of online trends, especially those that promise quick fixes to physical appearance. Consulting with qualified professionals, such as orthodontists or facial surgeons, is crucial if you have concerns about your facial structure. These professionals can provide evidence-based advice and treatment options.
