Ultherapy uses ultrasound targeting the 4.5 mm SMAS layer to stimulate deep...

https://rapid-wiki.win/index.php/If_I_Did_HIFU_Before_and_Saw_Nothing,_Should_I_Try_Ultherapy_Next%3F

Ultherapy uses ultrasound targeting the 4.5 mm SMAS layer to stimulate deep collagen over 3 to 6 months, offering gradual skin lifting. Compared to RF, which heats skin between 40 to 45°C for surface tightening, Ultherapy works deeper