Long-Term Correction of Nasolabial Folds Using Poly- L- Lactic Acid Microspheres: A Multicenter, Double-Blinded, Randomized Trial

Background: Correction of moderate-to-severe nasolabial folds (NLFs) is a key concern in aesthetic medicine. Poly-L-lactic acid (PLLA) microspheres, with biostimulatory properties, potentially offer longer-lasting results compared with hyaluronic acid (HA), the current standard of care. Objectives: The aim of this study was to evaluate the efficacy and safety of PLLA microspheres vs HA for the correction of moderate-to-severe NLFs. Methods: In this multicenter, randomized, double-blind, parallel-controlled trial, 252 participants were enrolled across 8 centers in China and assigned to receive either PLLA or HA filler. The primary endpoint was the effective correction ratio of the Wrinkle Severity Rating Scale (WSRS) at 48 weeks, assessed by blinded independent reviewers. Secondary endpoints included WSRS change, Global Aesthetic Improvement Scale (GAIS) scores (investigator- and participant-assessed), treatment frequency, and safety outcomes. Results: < .0001). HA outperformed PLLA at Week 4, reflecting its immediate effect, whereas PLLA showed superior outcomes from Week 36 onward with sustained improvement confirmed by WSRS and GAIS. PLLA required more frequent early treatments, whereas HA generally achieved correction with fewer sessions. Adverse events were mild and transient, with no serious complications in either group. Conclusions: Under current protocols, HA offers rapid improvement, whereas PLLA requires multiple early sessions but yields more durable correction up to 48 weeks with similar safety. Filler selection should be individualized according to patient priorities.