Author: Site Editor Publish Time: 01-05-2026 Origin: Site
Interest in buttock contouring has increased substantially in recent years. Data from the International Society of Aesthetic Plastic Surgery indicate that aesthetic procedures involving the buttocks rose by more than 60% between 2019 and 2023. While surgical approaches such as implants and autologous fat grafting remain effective, their longer recovery times and inherent procedural risks have driven demand for less invasive alternatives. In this context, hyaluronic acid (HA) fillers have emerged as a promising option due to their biocompatibility, predictable biodegradation, and favorable integration with subcutaneous tissue.
This prospective study was designed to evaluate the safety, durability, and patient satisfaction associated with hyaluronic acid buttock augmentation. Thirty healthy female participants were enrolled and treated with a cross-linked HA filler produced using a specific cross-linking technology (UPMax). The mean injection volume was approximately 44 mL per patient. Outcomes were assessed over 12 months using standardized photography, three-dimensional (3D) imaging, ultrasound examinations, and structured patient-reported satisfaction measures. A small exploratory sub-study in three participants additionally monitored serum hyaluronic acid levels during the first 90 days after treatment to gain insight into systemic metabolism.
Figure 1 | Buttock zoning diagram for hyaluronic acid filler treatment planning. The illustration demonstrates division of the buttock into four quadrants—upper outer, upper inner, lower outer, and lower inner—with the central intersection representing the primary injection focus. The hip dip region is highlighted as a key target area to ensure symmetrical contouring and harmonious volume distribution.
Treatment planning was performed with patients in a standing position. Vertical and horizontal reference lines were drawn to divide each buttock into four anatomical quadrants. Hip dips, when present, were marked as priority correction zones (Figure 1). Injections were then administered with the patient in the prone position using a 70 mm blunt-tip cannula. The filler was placed in the superficial subcutaneous plane, approximately 0.5–1 cm beneath the skin and above the superficial fascia.
For both safety and aesthetic outcomes, the upper outer quadrant was treated first, as it contributes significantly to buttock projection and lift. Additional filler was distributed based on individual anatomy, tissue laxity, and aesthetic goals, with total volumes not exceeding 60 mL. Gentle post-injection massage was performed to promote even filler distribution.
Table 1 | Demographic characteristics of the study population. Participant age, body mass index, Fitzpatrick skin phototype, and prior buttock treatment history are summarized.
Standardized 2D and 3D imaging demonstrated a clear increase in buttock volume and improvement in overall contour. Common aesthetic concerns, including hip dips and deep infragluteal folds, showed visible correction. Ultrasound imaging confirmed accurate placement of the filler within the subcutaneous layer. Over time, the injected HA gradually integrated with surrounding adipose tissue and underwent partial resorption, without evidence of migration, nodule formation, or fibrosis.
Figure 2 | Representative 3D imaging follow-up of a patient treated with 18 mL of hyaluronic acid filler. Images obtained before treatment and at 30, 90, 180, and 360 days demonstrate immediate volume enhancement and sustained contour improvement at one year, despite partial volume reduction.
Figure 3 | Representative 3D imaging follow-up of a patient treated with 60 mL of hyaluronic acid filler. This case illustrates more pronounced augmentation and lift, with marked contour enhancement maintained for at least six months.
Figure 4 | 3D imaging highlighting hip dip and infragluteal fold correction. Comparative images show effective filling of lateral depressions and softening of the infragluteal fold, with improvements persisting at 12 months.
Patient-reported satisfaction peaked at 30 days post-treatment, with 90% of participants reporting improvement. Satisfaction declined modestly over time, corresponding with gradual HA degradation, yet remained high: 86% at six months and 62% at 12 months. Importantly, no participant reported a worse outcome compared with baseline at any follow-up point.
Figure 5 | Global Aesthetic Improvement Scale (GAIS) scores over time. The distribution of GAIS ratings demonstrates sustained perceived improvement in the majority of patients throughout the one-year follow-up, with no reports of deterioration.
No serious adverse events were observed. Four mild adverse events were reported: one localized infection that resolved with oral antibiotics; two cases of intermittent, self-limiting swelling at later follow-up visits; and one case of discomfort due to localized overcorrection in the hip dip area. Ultrasound confirmed excess filler without inflammatory changes, and symptoms resolved fully following limited hyaluronidase administration.
In the exploratory sub-study, serum hyaluronic acid levels increased within the first week after injection, reached a transient peak at approximately 30 days, and returned close to baseline by day 90. These findings suggest that even relatively large volumes of injected HA can be gradually cleared through normal systemic metabolic pathways.
Figure 6 | Mean serum hyaluronic acid concentration over time (n = 3). Baseline levels increased after treatment, peaked at around day 30, and returned near pre-treatment values by day 90, indicating progressive metabolic clearance without sustained accumulation.
The results of this study support hyaluronic acid fillers as a viable option for non-surgical buttock augmentation when strict anatomical safety principles are followed. Use of blunt cannulas, superficial subcutaneous placement, and avoidance of medial danger zones are key factors contributing to a favorable safety profile. Compared with autologous fat grafting, which carries a documented risk of fat embolism, no comparable severe vascular complications have been reliably reported for HA-based buttock augmentation.
Figure 7 | Baseline ultrasound image (20 MHz) of normal buttock anatomy. The layered structure of skin, superficial fat, fascia, and deeper adipose tissue serves as a reference for post-treatment comparison.
Although hyaluronic acid undergoes gradual biodegradation, imaging findings indicate that aesthetic outcomes do not fully regress to baseline at one year. Partial integration of the filler with surrounding tissues and possible stimulation of tissue remodeling may contribute to the persistence of improved contour.
Figure 8–10 | Ultrasound evolution of hyaluronic acid filler over time. Immediate post-treatment images show well-defined, anechoic filler deposits in the subcutaneous layer. At one month, surrounding tissue demonstrates expected reactive changes consistent with early integration. At one year, blurred margins and reduced echogenic contrast indicate partial resorption and incorporation into native tissue, correlating with sustained contour support.
Study limitations include the relatively small sample size, absence of a control group, and limited duration of serum biomarker monitoring. Nevertheless, the combined use of imaging, patient-reported outcomes, and biochemical data provides meaningful preliminary evidence for the use of hyaluronic acid fillers in large-area body contouring.
In conclusion, this one-year follow-up study suggests that non-surgical buttock augmentation with cross-linked hyaluronic acid fillers is a safe, effective, and well-accepted approach for appropriately selected patients. It offers predictable aesthetic improvement lasting up to 12 months and represents a compelling option for individuals seeking buttock enhancement with reduced invasiveness and shorter recovery compared with surgical alternatives.
