Safety and efficacy of a novel non-invasive monopolar radiofrequency device for skin tightening in a porcine model in Republic of Korea: pre-clinical study

Abstract

Background: Monopolar radiofrequency devices for facial skin tightening offer a promising non-invasive approach that targets the deep dermis to prompt immediate collagen contraction and subsequent remodeling. However, non-clinical evidence supporting the efficacy and mechanisms of action of these treatments remains limited, despite their increasing use. This study aimed to evaluate the effectiveness and safety of a dualfrequency non-invasive monopolar radiofrequency (NMRF) device using a porcine model, directly comparing a conventional 6.78 MHz setting with a dual-frequency (6.78 + 2 MHz) mode. Methods: Female porcine subjects were treated using an innovative NMRF device (XERF; Cynosure Lutronic Inc.). Efficacy was assessed histologically for up to 1 month. Safety was evaluated through thermal skinsurface monitoring and standard assessments. Results: When compared with 6.78 MHz alone, the dual-frequency (6.78 + 2 MHz) mode produced greater immediate thickening and shortening of deep dermal collagen bundles and more prominent remodeling of subcutaneous fibrous septa. At 1 month, the dual-frequency treatment yielded larger increases in dermal collagen density, more regular bundle alignment, and higher elastin signals. Surface temperature remained below 43ºC, and no tissue damage was observed following NMRF treatment. Conclusion: Our research strongly indicates that immediate tissue contraction occurs following treatment and that dual-frequency application results in more substantial collagen reconstruction. In the long term, NMRF stimulates the production of new collagen and elastin. The dual-frequency mode enhances these effects, supporting its use in effective and safe skin tightening and rejuvenation.