Efficacy and Safety of Hyaluronic Acid Fillers for Horizontal Neck Lines: A Systematic Review and Meta-Analysis

Horizontal neck lines are a common aesthetic concern among aging and younger populations. Hyaluronic acid (HA) fillers are increasingly used in this region, yet their effectiveness, safety, and optimal application strategies remain under-investigated. This systematic review and meta-analysis, conducted in accordance with PRISMA guidelines and registered with PROSPERO (CRD42024550863), aimed to evaluate the efficacy and safety of HA fillers for horizontal neck lines. Comprehensive searches of Ovid MEDLINE and Embase were performed up to May 2024. Eleven studies (<i>n</i> = 379) met the inclusion criteria. Pooled analysis demonstrated significant improvements in the Global Aesthetic Improvement Scale (mean, 1.75, 95% CI, 1.53-1.96) and wrinkle grading (mean difference, 1.43, 95% CI, 0.72-2.15). Instrumental assessments confirmed enhancements in hydration, elasticity, and dermal structure. The pooled retreatment rate within 12 months was 50%, and the complication rate 14%, with only mild, transient effects reported. Patient satisfaction was consistently high. In summary, HA fillers represent an effective and well-tolerated option for treating horizontal neck lines, producing sustained improvements in both aesthetic appearance and skin quality. <b>Level of Evidence:</b> 4 (Therapeutic).