SYSTEM 5 - CHEMICALLY TREATED HAIR - FOR LIGHT THINNING HAIR. Prepare the scalp and hair for complete hair thickening treatment with Nioxin System 5 for Chemically Treated Hair with Light Thinning. The Pro-Color Shield technology removes sebum, fatty acids and other environmental residue from the scalp and hair. Nioxin shampoo deeply cleanses the scalp and provides thicker-looking hair. Nioxin cleanser is the first step of a 3-part Nioxin treatment, designed to strengthen the hair and amplify hair structure.