Monopolar radiofrequency (MRF) is a well-established modality for non-invasive facial rejuvenation; however, its clinical utility is frequently constrained by patient discomfort and inconsistent thermal delivery. This study evaluated the efficacy, safety, and mechanistic profile of a novel MRF system incorporating continuous water cooling (RF-CWC) designed to optimize thermal distribution and enhance patient tolerance. In a prospective, single-arm clinical trial involving 22 female participants, a single RF-CWC treatment utilizing region-specific static and sliding delivery modes yielded statistically significant improvements in jawline lifting, alongside a volumetric increase in the midface and a concomitant volumetric reduction in the lower face (p < 0.001) over an 8-week follow-up period, with no adverse events reported. To elucidate the underlying cellular mechanisms, the system was further evaluated using an ultraviolet B (UVB)-induced ex vivo human skin model and an in vivo porcine model. Histological, immunohistochemical, and ELISA analyses revealed that RF-CWC effectively mitigated UVB-induced dermal degradation ex vivo by significantly up-regulating elastin, insulin-like growth factor, and hyaluronic acid, while down-regulating matrix metalloproteinase-1, interleukin-1α, and heat shock protein 72 (p < 0.05). Furthermore, the in vivo model demonstrated time-dependent increases in collagen types I and III and elastin without thermal tissue damage, with the sliding mode and higher shot counts correlating with enhanced extracellular matrix (ECM) remodeling. Comparative analyses demonstrated that RF-CWC achieved superior ECM restoration and reduced inflammatory cell infiltration relative to traditional cryogen spray-cooled RF systems. Taken together, these findings suggest that the RF-CWC system may promote robust ECM remodeling and significant facial neocollagenesis while minimizing inflammatory responses, potentially presenting an optimized, highly effective, and patient-friendly advancement in MRF technology.
Roh et al. (2026) studied this question.