Technology guide
How ultrasound acts on fat cells
Ultrasonic cavitation relies on a simple physical phenomenon: microbubbles that form and then implode in the fatty tissue. A step-by-step explanation.
Low-frequency ultrasound
Ultrasound consists of inaudible sound waves above 20 kHz. Aesthetic cavitation uses a frequency of about 40 kHz. The wave causes phases of compression and rarefaction to alternate in the tissue.
The formation of microbubbles
During the rarefaction phases, local pressure drops and tiny gas bubbles form in the fluid between the cells. Cycle after cycle, these bubbles grow until they become unstable.
Implosion
During a compression phase, the unstable bubble collapses abruptly. This implosion produces a shock wave and a microjet of fluid that are highly localised, on the scale of a few micrometres.
The effect on the adipocyte
These forces weaken the membrane of neighbouring fat cells, which release their triglyceride content. Some of the cells that are only damaged then undergo programmed cell death in the following days.
Clearing the released fats
The released fats are taken up by macrophages and then cleared via the lymphatic system. This clean-up takes several weeks: that is why cavitation is performed as a course of treatment and combines well with drainage.
What to know in the treatment room
The client mainly feels a vibration, sometimes a slight buzzing or warmth at the end of the session. It is not advisable to treat an area with cavitation that has just been treated with cryolipolysis: space the two techniques several weeks apart.