Shampooing twice a day is totally unneccesary, but may be required for those who become oily. Before I started my regimen, iIwas extremely oily, so much so that I had to wash my hair twice a day and the face 4 or 5 times. The nizarol shampoo (2%) solved all that. Now I do not become oily at all. It is also very important that you get rid of oily and fatty foods from your diet, regular excerise is also important. If you excrete a lot of sebum it is unlikely that you will get a lot regrowth, so if by any chance you are extremely oily, I would recommend the use of nizarol everyday until the problem goes away. Personally, I only shampoo with Nizarol every 3rd day after gym or jogging.