Conditioner makes mine look thinner too, Katy. I've just started using the Fibrology. After 3 uses, I definitely think it has made a difference to my baby fine hair, which does seem to have a little bit of body now. One drawback is that it doesn't get on with the Batiste I've been using - a quick spray of the dry stuff now and my hair looks lank and greasy. This didn't happen with the shampoo I normally use - again L'Oreal, but the EverPure that has no sulphates in and made my hair nice and shiny.
It's a shame L'Oreal can't combine the two formulae somehow! Of course I'll be trying to mix the two now and it'll all go horribly wrong....