A Systematic Review of Injectable Treatment Options for Horizontal Neck Rhytides

ABSTRACT Background Horizontal neck rhytides, commonly termed “tech neck lines,” represent an increasingly common aesthetic concern across age groups. Injectable treatments, including hyaluronic acid (HA) fillers and neuromodulators, are frequently employed; however, optimal modality selection and treatment protocols remain unclear. Objective To systematically review and compare the efficacy, durability, injection techniques, and safety profiles of hyaluronic acid fillers and neuromodulators for the treatment of horizontal neck rhytides. Methods A systematic literature review was conducted using PRISMA 2020 guidelines. PubMed, Embase, and Cochrane CENTRAL were searched from inception through January 3, 2026. Eligible studies included human clinical trials evaluating injectable HA fillers or neuromodulators specifically for horizontal neck lines. Outcomes were assessed using validated aesthetic scales, including the Transverse Neck Line Scale (TNLS), Allergan Transverse Neck Line Scale (ATNLS), Global Aesthetic Improvement Scale (GAIS), and Wrinkle Assessment Scale (WAS). Risk of bias was evaluated using Cochrane RoB‐2 and ROBINS‐I tools, with certainty of evidence assessed via GRADE. Results Twelve studies met inclusion criteria, comprising ten HA filler studies and two neuromodulator studies. HA fillers demonstrated more robust data, durability, consistency, and patient/physician satisfaction according to aesthetic scales. Crosslinked HA fillers were more frequently utilized, though non‐crosslinked formulations also demonstrated favorable outcomes for similar durations. Neuromodulators yielded modest improvements, with peak efficacy observed at 8–12 weeks and enhanced results when combined with HA filler. Both modalities exhibited favorable safety profiles, with predominantly mild and self‐limited adverse events. Conclusion Both HA fillers and neuromodulators are effective for the treatment of horizontal neck rhytides. The current evidence base for HA fillers is more extensive and suggests consistent and durable improvement, particularly for static lines; however, direct comparative studies with neuromodulators are limited. Further head‐to‐head trials are needed to determine relative effectiveness and optimize treatment strategies.