Assessment of Hyaluronic Acid Filler in Gluteal Augmentation and Contouring: A 1-Year Prospective Study.

BACKGROUND: Minimally invasive gluteal augmentation techniques have gained popularity as alternatives to surgical procedures, offering reduced downtime and an improved safety profile. Hyaluronic acid (HA) fillers have emerged as a promising option due to their biocompatibility and favorable rheological characteristics. OBJECTIVES: To evaluate safety, efficacy, durability, and patient satisfaction of a cross-linked HA filler for gluteal augmentation and contouring over a 12-month period, and to conduct a pilot exploratory substudy assessing serum HA levels up to 90 days. METHODS: This was a 12-month, prospective, multicenter, open-label study including 30 healthy women undergoing gluteal augmentation with a cross-linked HA filler (UP Max). Each participant received up to 60 mL of HA filler, administered using a quadrant-based technique, guided by anatomical landmarks. Outcomes included safety (adverse events), efficacy (standardized photography and 3D imaging, ultrasound), durability and patient satisfaction. In addition, serum HA levels were measured in a pilot subgroup of patients. RESULTS: The mean injected volume was 43.60 ± 11.48 mL. Patient satisfaction peaked at Day 30 (90%) and declined to 62% at 12 months, consistent with HA biodegradation. Ultrasound confirmed subcutaneous placement and progressive filler absorption and integration, with no signs of migration, fibrosis or nodularity. Serum HA levels showed a transient increase at Day 30 and returned to near baseline at Day 90. No serious adverse events were reported, and minor complications were infrequent. CONCLUSIONS: HA filler demonstrated a favorable safety profile, high patient satisfaction, and aesthetic improvements over 1 year. These findings support its use as a safe and effective option for nonsurgical gluteal augmentation and body contouring.