Kérastase Chronologiste Longevity Potion is a revitalizing leave-in scalp serum designed to help preserve hair's youthful appearance. Infused with 3% Pro-Xylane™ and Ochrophyta Algae, its lightweight formula targets signs associated with hair aging, including loss of density and vitality, while helping hair look thicker, healthier and more youthful. Helps support hair density and vitality Revitalizes and cares for the scalp Helps hair appear thicker and healthier Lightweight, fast-absorbing leave-in formula Infused with 3% Pro-Xylane™ and Ochrophyta Algae HOW TO USE Use after shampooing for a one-month period. Shake well before use. On towel-dried scalp and roots, apply 5 doses section by section, using one pipette filled to the marked line per dose. Do not rinse.