Pureology PureVolume Shampoo is what my friend used when she was going through the same thing. Her hair was thinning and falling off that's why she consulted to a derma, and Pureology was the product that the derma suggested. It's a bit pricey but it helps. I'm actually saving to have this next month because my hair lacks volume. I already put this on my ReMINEd
wish list so I can always keep track of this goal.