Proctor is a smart guy and has some research to validate his claims. I use only the shampoo 2-3 times a week along with 1/4 proscar and minox 5%. The Nano shampoo is pricey but I use a normal shampoo first and then use the Nano after and leave it on 3-5 minutes. This way I can make a bottle last at least 6 months or even longer. I am convinced that it helps.