Kerastase Resistance Extentioniste Hair Masque is ideal for unconditioned brittle hair, this deep restorative mask penetrates hair to treat and restore strands back to lustrous health. Damaged brittle hair is fortified, leaving it soft ideal for unconditioned brittle hair, this deep restorative mask penetrates hair to treat and restore strands back to lustrous health. Damaged brittle hair is fortified, leaving it soft and shiny. Actives delivered through the creatine r and acid maleic contained in the formula help boost hair fiber to reinforce strands all the way to the tips. Split ends are repaired and breakage is prevented allowing hair to reach new healthy lengths.