Submental fullness has been associated with being perceived as unattractive. Technology combining radiofrequency and muscle stimulation offers submental contouring through fat reduction, muscle stimulation, and skin tightening. This study aims to demonstrate the effectiveness and safety of fat reduction aspect with a novel submentum applicator delivering HIFES and synchronized radiofrequency+ (RF+) energies. Six white pigs (sus scrofa domesticus, n = 6, 60-80 kg) were recruited for this study, five in the active group (n = 5) received four treatments on the abdominal area, one sow served as a control (n = 1). Ultrasound, histological, and RT-qPCR methods were used as evaluation methods. Fat thickness decreased at 1 month by -17.35% and at 2 month by 31.40%. Proapoptotic caspase-9 gene expression increased (at 1 h, 6 h, 24 h to +43.45%, +21.22%, -8.36%), as well as caspase-3 (+15.28%, +21.77%, -6.71%), while bcl2l1 activity decreased (-11.46% at 1 h, -17.02% at 6 h, -3.9% at 24 h). While the AI in the control animal had minimal change (at 1 h -0.08%, at 6 h -0.09%, and at 24 h -0.025%), the active group's AI increased from the baseline of 9.14 to 44.85 at 1 h (+391%), peaked at 6 h to 53.50 (+485%), and at 24 h to 38.17 (+318%). The study results indicate the efficacy and safety of subcutaneous fat reduction following the novel technology combining HIFES and RF+ energies, designed to target small localized areas.