Nioxin - System 4 Shampoo 300mlNioxins cleanser shampoo System 4 for colored 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 the hair and scalp for a complete hair thickening treatment with Nioxins three part System 4. This professional derma purifying, color safe Cleanser Shampoo removes dirt, excessive oil and other environmental residues from the scalp and hair.