Concentré Décalcifiant Ultra-Réparateur by Kérastase is a dual-action decalcifying and repairing pre-shampoo hair treatment for damaged hair from Kérastase. Removes calcium and reinforces hair strength, leaving it stronger, smoother, and shinier – as if renewed. This treatment’s concentration of acids has a dual action: it decalcifies hair from this calcium overload, and repairs it from the inside out, restoring hair strength, and reversing its stiff, dull appearance. A concentration of acids that: Decalcifies and dramatically reduce persistent damage; Recreates 99% of hair’s original strength*; Penetrates deep in the hair to eliminate calcium overdose; Reverse stiffness and dullness; 75% more shine** Reconnect broken link between keratin chains; +97% inner structure reinforcement** 93% less breakage** Hair is strengthened from within 69% inner strength reinforcement** *instrumental test after 5 uses of Concentré + Bain + Masque Première **Instrumental test after 1 application of ConcentréUse:Apply generously on wet lengths before shampoo and massage throughout. Leave on for 5 minutes. Don’t rinse and layer Première Bain directly on top to maximize efficacy. Rinse and follow with Première Fondant or Mask. Kérastase Première Concentré Décalcifiant Ultra-Réparateur Pre-Sh