Shampoo that claims to help grow new hair: scam or not? For the most part, this is a scam. The great majority of hair loss in men and women is caused by a hormonal variant of testosterone in the scalp called DHT, which stands for dihydrotestosterone. DHT is made in the body when an enzyme called 5 alpha reductase acts on testosterone. Excess DHT in the scalp causes hair follicles to shrink slowly and die. This can happen in women too, but to a lesser degree since women naturally produce much less testosterone than men do.

People can be quite emotional when it comes to their hair. The way we wear our hair broadcasts several things about us, including our general level of health and our age. Naturally, when people encounter what they consider to be hair problems like graying or balding, they react emotionally, and may be prone to accepting some of the myths about hair that never seem to die out.