SYSTEM 6 - CHEMICALLY TREATED HAIR - FOR PROGRESSIVE THINNING HAIR. Refresh the scalp and increase your hair volume with Nioxin’s 3-part System 5 Scalp & Hair Treatment for Chemically Treated Hair with Light Thinning. Thanks to its Transactive Delivery System 2.0, this professional product refreshes the scalp and gives a healthy shine to your hair. The volumizing Nioxin leave-on treatment helps provide thicker-looking hair by increasing the fullness of each hair strand. Nioxin’s Scalp & Hair Treatment is the final step of the 3-part System, which amplifies hair texture while protecting against breakage.