Nioxin Pro Clinical's System Kit 1 is designed for natural, untreated hair with light thinning. Clinically and dermatologically tested, this nourishing and protective leave on treatment strengthens each strand from within, resulting in thicker, fuller hair.Formulated with a powerful blend of niacinamide, biotin and caffeine to help nourish the hair root, stimulate hair follicles and strengthen the hair. Nioxin System 1 Scalp + Hair Thickening Treatment enhances the thickness and fullness of your natural hair. The lightweight formula adds body to your hair, making it look thicker and fuller.Formulated with Niacinamide, this Scalp + Hair Thickening Treatment helps balance the scalp, creating a healthy environment for hair growth. In addition to its strengthening and nourishing properties, Nioxin System 1 Scalp + Hair Thickening Treatment adds moisture and shine to your hair. To use, apply Nioxin System 1 Scalp + Hair Thickening Treatment to towel-dried hair, focusing on the scalp and areas of concern. Massage gently to ensure even distribution. Do not rinse out. Style as desired. For optimal results, use alongside Nioxin System 1 Scalp + Hair Shampoo and Conditioner.