Boost shine and banish split ends with Kerastase resistance Masque extentioniste, an intensive hair mask that nourishes brittle and damaged hair. Enriched with Creatine R and maleic acid. Hair appears softer, smoother, detangled & more manageable. Repairs bonds within hair structure while improving overall strength & elasticity. Infused with maleic acid to strengthen & seal the cuticle with a uniform coating from root to ends. Blended with ceramide to provide surface recovery for beautiful hair. Formulated with creatine, an amino acid that penetrates deep to reinforce the hair fiber.