Dr. Alisa Yamasaki uses a variety of hyaluronic acid-based fillers for lip augmentation, which are popular for their natural-looking results and safety. These include well-known options like Juvederm (such as Juvederm Ultra XC and Volbella XC) and Restylane (Restylane-L and Restylane Silk), which help add volume, smooth vertical lines, and enhance lip definition.