The number one selling salon brand for thicker, fuller looking hair*. Nioxin is the only professional haircare brand endorsed by the Institute of Trichologists for thinning hair. Nioxin System 4 Scalp Treatment for fine hair, chemically treated, noticeably thinning hair is a daily leave-in scalp treatment with sunscreen factors. Protects scalp skin from the damage of UVA/B rays and delivers essential botanical, nutrients, antioxidants & vitamins. Shields against residues & DHT build up on scalp to create & maintain a healthy scalp environment. Helps improve appearance of thinning hair. *Value Data Kline & Company