How Often Should I Wash?“It is a personal choice how often to shampoo your hair,” says Dr. Antonella Tosti, Dermatology Professor at the University of Miami, “but I advise my patients to shampoo at least twice week and reassure them it is OK to wash every day. Be sure when you wash to focus on the scalp, and I recommend washing after exercise as sweat can lead to scalp irritation.” Additional factors other than exercise frequency that influence how often one washes one’s hair are the climate in which they live, hair thickness (those with finer hair show grease more easily), whether they tend to have oily, dry or combination hair, and styling product usage.