What causes the immediate effect after the HiFu procedure and what is it due to?

Many patients notice a slight lifting and tightening immediately after the HiFu procedure, which often raises questions: “How is this possible?” and “Does this mean that the effect is already there?” In fact, this initial result is due not to newly formed collagen, but to physiological reactions triggered by the ultrasound energy.

1. Thermal shrinkage of collagen fibers

HiFu (High-Intensity Focused Ultrasound) works by precisely targeting heat energy to the deep layers of the skin, including the SMAS layer – the same layer that is treated in a surgical facelift. When the tissue is heated to around 60–70°C, this results in immediate contraction of collagen fibers, which react to heat by shrinking and thickening. This thermal contraction is the cause of the visible tightening effect in the first minutes or hours after the procedureIt is important to know that this effect is temporary and partly optical.

2. Temporary swelling and inflammatory reaction

After the procedure, you may experience some slight swelling and redness in the treated area. This is due to the body's inflammatory response to the heat and is part of the natural healing process. The swelling may give the impression of additional tightening and volume, but this effect is temporary and usually subsides within a few days.

3. Stimulation of neocollagenesis

The real rejuvenation process begins in the following weeks, when fibroblasts – the cells responsible for the production of new collagen and elastin – are activated. The full effect develops gradually and reaches its maximum between 2 and 3 months after the procedure.