Redken Extreme Length Shampoo is a strengthening shampoo with biotin that gently cleanses while helping to fortify strands from root to tip. This biotin-infused shampoo helps to strengthen damaged hair so it can grow longer and helps to reduce the look of split ends. When used as a full system of Shampoo, Conditioner, and Leave-in Treatment, it helps you achieve your maximum hair length, with up to 6 inches of growth in one year. *When used as a system of Extreme Length Shampoo, Conditioner and Sealer vs non-conditioning shampoo.