There is a host of reasons why this could happen, but IF it is caused by a medication buildup there might be help. My hairdresser said I had a medication buildup and sold me nioxin shampoo. She didn’t really think all the scalp treatments would make a big difference since I wash my hair every other day. It did help some. I can’t say it all came back but, I did notice quite a bit of hair growing in that is shorter than the rest.