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.

Synovial fluid (SF) rheological properties deteriorate progressively in knee osteoarthritis (OA) due to a reduction in hyaluronic acid (HA) concentration and molecular weight, compromising joint lubrication and load distribution. Restoring these properties through intra-articular viscosupplementation with HA is a widely used therapeutic strategy. However, commercially available linear HA formulations differ substantially in their mechanical behavior, and single-parameter assessments are insufficient for capturing their functional differences. In this study, eight commercially available intra-articular linear HA hydrogels—TrHLINE 1%^®, TrHLINE 2%^®, Hyalubrix^®, Hyalgan Bio^®, Pronolis^® HD 2.5%, Biolevox™ HA ONE 2.5%, Suplasyn^®, and Arthrum H 2%^®—were evaluated under standardized conditions using steady-state viscosity, mechanical stress response, first normal stress difference (N1), storage and loss moduli (G′, G″), loss factor (tan δ), and elasticity percentage. Results revealed three distinct functional profiles: lubricant-oriented with low to moderate structural organization (Hyalgan Bio^®, Suplasyn^®, TrHLINE 1%^®); balanced viscoelastic with sustained structural persistence (TrHLINE 2%^®, Hyalubrix^®, Arthrum H 2%^®); and high initial rigidity with reduced dynamic persistence (Biolevox™ HA ONE 2.5%, Pronolis^® HD 2.5%). These findings demonstrate that multi-parametric rheological benchmarking effectively discriminates functional differences among HA viscosupplements and supports indication-oriented product selection based on OA severity and patient mechanical demand.