The shampoo designed for colour-treated hair doesn't make the colour stronger, it sort of just makes it shinier and I guess helps to stop it from fading. I know that I think mine hasn't faded and then when I use it I'm like 'wow that had faded more than I thought'. So it will enhance the colour and probably make your highlights more noticeable, which could give the impression that your hair is blonder, but it won't actually make all of your hair blonder.
