Abstract
BACKGROUND: Skin aging research often focuses on the dermis, overlooking the significance of the retinacular cutis (RC) in aging. This study aimed to investigate the efficacy, safety, and effect of an injectable solution containing hyaluronic acid, amino acids, and peptides, on facial sagging and laxity by targeting the RC. METHODS: This single-center observational study recruited 28 female volunteers aged 25-65 years. The participants received four monthly injections of the studied solution. Objective measures included skin hydration, elasticity, color, thickness, collagen density evaluated via DermaLab Combo and high-resolution ultrasound imaging. Subjective measures included participant satisfaction evaluated using the Global Aesthetic Improvement Scale (GAIS). Adverse effects were monitored throughout the study period. RESULTS: Significant improvements were observed in skin hydration, elasticity, and collagen density after treatment. Hydration increased by 25.9% at T1 (30 days after last session), sustaining a 15.9% increase at T2 (120 days after last session). Elasticity improved by 29.2% at T1 and 20.7% at T2. Collagen density increased by 20.27% at T1 and 16.71% at T2. Self-reported GAIS scores showed consistent increases. Adverse effects were minimal and included only transient ecchymosis and mild pain. CONCLUSION: Injections of the solution had a substantial hydrating effect, enhanced elasticity, and increased collagen density in the RC and dermis. Results persisted at the 120-day follow-up, indicating sustained benefits. Hence, this injectable solution may offer a safe and effective non-invasive treatment option for improving skin laxity and sagging, targeting the RC and other deep connective tissue such as retaining ligaments.