It varies by programme and is often added as a finishing step. It is not a treatment with a fixed count of its own — whether it is needed depends on what came before it. With repetition, the skin becomes more hydrated and the tone brightens as the changes accumulate.

Added at the end of a care session, applied ingredients absorb better. The vibration shakes the gaps in the dead-skin layer open, so more of what was applied earlier goes in than would otherwise. It aids circulation on its own too, but it is more efficient when there is something to deliver.

Both help absorption. Iontophoresis pushes ingredients in with a current; Sonocare widens the pathways with ultrasound vibration so they can enter. Ultrasound also aids circulation, so it is often chosen when puffiness or a congested feeling is present too. Neither produces an effect alone — what was applied first decides the result.