I had a huge problem with color change with the Ion brand keratin I used to use. I assume the formula is pretty similar to the Organix kind. The color of it was actually kind of a caramel color, but I always thought my hair looked orange from the high heat of my flat iron. I'm not really sure- if you look at the pictures of my hair in my separate review of this product you can see how yellowish it looks. However, my roots are my natural dirty blonde color and Uncurly didn't turn them orange. As far as I know keratin shouldn't change the color of your hair- the last time I got my hair cut my stylist was pretty concerned that it changed my color so much. That's part of the reason I wanted to try something a bit better.
The color of the Uncurly treatment is light purple. I'm not sure why its that color, but I sort of assumed having it purple would maybe neutralize any kind of burnt yellow. That's probably not true but I felt a lot better about putting that in my hair than the caramel colored Ion!
I'm really happy with my results with Uncurly- I had planned to buy some 200 dollar bottle of QOD or something because I was sick of my results with Ion. But 80 dollars seems like a great deal in comparison. Hope this helps!