NIOXIN Scalp Relief Soothing Serum is the final step of a three part regimen, specially formulated to soothe the scalp while thickening the hair. A leave-on treatment that immediately relieves a dry, sensitive and itchy scalp, while helping to increase the thickness of each hair strand. Formulated without parabens and colorants. With Aloe Vera, a scalp neutral pH, and a clean label fragrance.