Efficacy and Safety of a Poly-L-Lactic Acid Filler for Temporal Augmentation: A Randomized, No-treatment Control, Evaluator-blinded, Multicenter Study

Abstract Background Temple hollowing represents a prevalent aesthetic concern traditionally addressed with autologous fat grafting or hyaluronic acid fillers. Poly-L-lactic acid (PLLA) offers gradual, collagen-mediated volumization and is increasingly utilized for soft-tissue augmentation. Nevertheless, to date, no approved study has evaluated its use for temporal augmentation. Objectives To evaluate the efficacy and safety of a PLLA facial filler for the augmentation of temple hollowing. Methods This randomized, no-treatment control, evaluator-blinded, multicenter clinical trial enrolled 174 participants with moderate to severe temple hollowing, randomized 2:1to the treatment or control group. The treatment group received 2 to 3 sessions of PLLA bilateral temporal injections with a 12-month follow-up, while the control group received no treatment within 6 months after randomization. Efficacy was assessed using the Allergan Temple hollowing Scale (ATHS), Global Aesthetic Improvement Scale (GAIS), three-dimensional volume change of temples, and participant-reported satisfaction. Safety evaluations included adverse events (AEs), injection-site reactions, vital signs, and laboratory tests. Results At month 6, 96.5% of participants in the treatment group achieved at least 1-grade improvement on the ATHS, in contrast to 0% in the control group (P 0.0001). Consistent and significant improvements were observed across all secondary endpoints, including ATHS efficacy rates assessed by both blinded evaluating and injection investigators at all follow-up visits up to 12 months, GAIS improvement rates, and temporal volume measured by 3D imaging. Aesthetic improvement and participant satisfaction were rated highly at all follow-up visits. PLLA was safe and well tolerated, with no therapy-related adverse events reported. Conclusions PLLA facial filler effectively improved temple hollowing and achieved aesthetic enhancement for up to 12 months with an excellent safety profile.