Kerastase's Fusio-Dose Booster Nutrition helps boost the hair's color while adding texture and lifting the roots. This concentrated formula penetrates deep into each strand, infusing them with nourishment without weighing them down.The hair is left with instantly noticeable and long-lasting healthy results. This Booster must be added to one of Kerastase's Fusio-Dose Concentres , creating a completely custom haircare experience.