Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a deep...

https://landensnewperspective.hexaforgey.com/posts/is-numbness-after-hifu-normal-or-a-red-flag

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a deep lift, with results peaking around 3 to 6 months. Compared to RF, which heats skin to 40-45°C mainly for collagen, Ultherapy reaches deeper