Viscoelastic Properties and Enzymatic Degradation of Crosslinked Hyaluronic Acid for Deep Dermal Filler Use.

Crosslinked hyaluronic acid dermal fillers are widely used for non-permanent aesthetic enhancement, offering safe and effective solutions for facial volume restoration. Specific formulations are designed for targeted facial regions, with highly crosslinked hydrogels often recommended for volumizing areas such as the jawline, chin, and cheeks due to their structural properties. While elasticity and viscosity are commonly evaluated, broader comparative analyses remain limited. In this study, we assess five commercially available HA-based fillers with similar HA concentrations, all optimised for volume enhancement. Alongside widely used reference products, we evaluate BtHCROSS 2%^®, a novel formulation not previously compared to established fillers. We examined the degree of chemical modification, mechanical viscoelastic behaviour, susceptibility to enzymatic degradation by hyaluronidase, and injection force. While all tested fillers are suitable for volume restoration, BtHCROSS 2%^® demonstrates a distinctive combination of mechanical adaptability, structural support, enzymatic resistance, and low injection force, making it a versatile option for practitioners.