Poly-L-Lactic Acid Skin-Tightening Protocol for Improvement of Lower-Face Laxity in Asian Patients: A Prospective Three-Dimensional Imaging and Ultrasound Assessment Study

Objective To evaluate longitudinal lower-face tightening after an injectable poly-L-lactic acid formulation (PLLA-SCA) in Asian patients using prospective 3-dimensional imaging and high-frequency ultrasound endpoints. Methods This prospective single-arm cohort enrolled 80 Asian adults from 2022 through 2025 with mild-to-severe lower-face laxity. Participants received PLLA-SCA at baseline and week 6; a third session was administered at week 12 only for grade 4 laxity or inadequate early response. At each session, reconstituted PLLA-SCA was placed with a cannula across the lateral lower cheek, mandibular retaining-zone transition, prejowl sulcus, and subdermal mandibular border according to the standardized protocol. Participants were followed at weeks 4, 12, and 24. The primary endpoint was 3-dimensional lower-face volume gain at week 24. Secondary endpoints included jowl descent, mandibular dermal thickness, dermal echogenicity, elastography-derived subcutaneous stiffness, FACE-Q satisfaction, investigator-rated aesthetic improvement, and adverse events. Results At week 24, mean lower-face volume gain was 1.64 mL (95% CI: 1.55–1.73; P <0.001). The mean jowl descent decreased by 0.96 mm (95% CI: −1.02 to −0.90; P <0.001), while dermal thickness increased by 0.18 mm (95% CI: 0.17–0.20; P <0.001). Week 24 GAIS response, defined as much improved or very much improved, was 97.5%. The most common adverse events were transient swelling, bruising, and tenderness. No treatment-related vascular adverse event, defined as suspected vascular occlusion or an associated ischemic complication, was recorded. Conclusion A PLLA-SCA protocol was associated with progressive lower-face tightening through 24 weeks in this Asian cohort. Computer-derived 3-dimensional measurements quantified surface-volume gain and jowl-position change, whereas ultrasound quantified dermal thickness, echogenicity, and subcutaneous stiffness. These objective measures complemented the clinician-rated GAIS and patient-reported FACE-Q results; their concordance supports measurable structural and perceived improvement, although the single-arm design does not establish causality or histologic remodeling.