It is not often I say this, and I'm not claiming it's an actual miracle worker or anything, but I have been using the No7 Vitamin C treatment morning and evening since Friday and I do believe that my skin looks better. Brighter, smoother, just...better. (For reference, I am early 40s with combination skin, and quite a greasy T zone. Nice.)
I don't think it would be suitable if you have very sensitive skin though, as I find it tingles a bit (doesn't sting though, just tingles) when I put it on.