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

https://gunnerawsh736.cavandoragh.org/is-it-normal-for-results-to-be-progressive-after-ultherapy

Ultherapy uses ultrasound energy targeting the 4.5 mm SMAS layer to stimulate collagen deep under the skin, with results peaking around 3 to 6 months