darkening effects are usually caused by some holding agent, such as those found in gels or sometimes even pomades.
How much hold do you need? If you need none - very little I'd suggest looking into the oleo-relax line by kerastace. http://www.kerastase-usa.com/_en/_us...Fc7AKgodq31Ngw
not sure what their uk site, is, but you get the idea.
That is one of the best anti frizz lines out there. Bad shampoos can often cause frizz by being to dry. So look for something that's moisturizing or oil based. i.e. kerastace oleo-relax. I'd recommend the shampoo, conditioner, and the oleo relax leave in here - (number #3) http://www.kerastase-usa.com/_en/_us...rebellious.htm
If you need more hold, i'd suggest trying a product which 'dirties' up your hair, and see if that provides enough hold i.e. - bumble and bumble grooming creme
if you still need more hold I'd cocktail it grooming creme with styling creme, or even just use styling creme straight, though you might again get a slight 'darkening effect' by using styling creme straight - http://www.bumbleandbumble.com/produ...eme/index.tmpl
pm me if you have any other questions.