The "4.3" technique is a hybrid lip augmentation approach that combines the aesthetic benefits of the vertical-lip technique with the fewer entry points of the retrograde linear technique. This method aims to create natural-looking, harmonious, and defined lips using hyaluronic acid (HA)-based fillers, to enhance volume and contour. The objective of this study is to evaluate the effectiveness, safety, and reproducibility of the "4.3" technique in achieving natural lip augmentation with minimal filler volume and reduced injections. This technique is applied to improve the shape and volume of the lips while minimizing the risk of complications. The technique was applied to male and female patients with standard anatomical features who desired subtle enhancements in lip contour, projection, and volume. The procedure involved four injections in the upper lip and three in the lower lip, using a combination of retrograde linear and vertical techniques. A total of 0.7 mL of HA filler were used for each patient. The "4.3" technique achieved consistent and aesthetically pleasing results across all patients, with improvements in lip volume, shape, and definition. The reduced number of injections minimized discomfort and risk of vascular complications. The use of Tri-Hyal technology contributed to smooth, plump lips with harmonious proportions. The "4.3" technique is a standardized, intuitive, and reproducible method suitable for most patients, regardless of sex. It allows for natural-looking lip augmentation using a reduced volume of filler and fewer injections, making it a safe and effective option for enhancing lip aesthetics.