Technology guide
HIFU: high-intensity focused ultrasound
HIFU concentrates ultrasound on a precise point beneath the skin to create a small thermal point there. How it works, treatment depths and differences from radiofrequency.
Definition
HIFU (High Intensity Focused Ultrasound) is a non-invasive firming technology. A treatment head concentrates ultrasound at a given depth and creates thermal coagulation points there, without damaging the surface of the skin.
The physical principle
A piezoelectric crystal converts electricity into ultrasonic vibrations. An acoustic lens makes them converge, just as a magnifying glass concentrates sunlight. At the focal point, the energy is converted into heat; before and after this point, it remains low.
What happens in the skin
At the heated point, the collagen fibres contract immediately, which can give a slight tightening effect. The main effect comes afterwards: the micro-lesion triggers natural healing and the production of new collagen over several months. The skin gains in thickness, firmness and elasticity.
Three depths
The 1.5 mm heads work on the superficial part of the skin (texture, fine lines), the 3 mm heads on the dermis (firmness, wrinkles) and the 4.5 mm heads on the SMAS, the fibromuscular layer addressed in a surgical facelift (facial contour, jowls). A complete protocol often combines several depths on the same area.
HIFU or radiofrequency?
HIFU delivers precise thermal points at depth, in one to three sessions, and is suited to facial lifting. Radiofrequency heats in a more diffuse and superficial way, over a longer course of treatment, and is well suited to the body and to sensitive clients. The two can be combined.
In practice
Sensations vary with depth, the most superficial head often being the most sensitive. Redness and slight swelling are common and temporary. For 24 to 48 hours, avoid sun, sauna, intensive exercise and irritating active ingredients.