i used wen as well and i had the same problem as belle who wrote in previously. My hair was severly damaged after just 2 washings.
I do believe it isnt good for all hair types and i should be used cautiously.If your lucky and it works for you then good for you. If you haven used it yet and your thinking of trying , please think twice .Also, Make sure you dont use a chi blowdrier with it.
They tend to be hotter then other driers and i believe that made it worse.I too now have keratin extensions as i had to cut off quite a bit of hair. It was not repairable.
Product or Service Mentioned: Wen Hair Care.