Booster Ionium: The ionium molecules improve smoothness of hair. Ionium brings in-depth nutrition and anti-dryness protection for smoothness and shine. Penetrates directly into the core of the hair filament to develop an instant effect. Intense nutrition. Specially developed for long-lasting shine to bring in the hair. All boosters are combinable. To achieve even greater effect, you can use up to 2 K©rastase Fusio-Dose Booster.