SYSTEM 3 - COLOURED HAIR - FOR LIGHT THINNING HAIR. Refresh the scalp and increase hair volume with Nioxin’s 3-part System 3 Scalp & Hair Treatment for Colored Hair with Light Thinning. This diameter-increasing professional product refreshes the scalp and gives a healthy shine to your hair. With its Transactive Delivery System 2.0, the volumizing Nioxin leave-on treatment helps provide thicker hair by increasing the fullness of each hair strand. Nioxin Scalp & Hair Treatment is the final step of the 3-part System, which amplifies hair texture while protecting against breakage.