The NIOXIN 3-Part System 6 Cleanser Shampoo for Chemically Treated Hair with Progressed Thinning is the first step of a three part Nioxin regimen, specially formulated to strengthen the hair and amplify hair structure. It PREPARES HAIR AND SCALP for a complete HAIR THICKENING TREATMENT with Nioxin’s three part System 3. This professional derma-purifying Cleanser Shampoo removes dirt, excessive oil and other environmental residues from the scalp and hair.