The main component of Tongyan Needle is poly-L-lactic acid, which is a natural substance in the human body. After injection, it can stimulate the growth of collagen in the deep layers of the skin and make the skin gradually fuller. Autologous collagen will start slowly after 3-6 months of injection. Growth is the best choice to maintain a natural youthful state. It also has the reputation of "Tian Hou Needle", and has obtained dual clinical approvals from the US FDA and the Canadian Health Agency.