I have to say that if yes looking for immediately blonder hair, this is t going to work out for you. But it certainly makes my long, curly, blonde hair shinier and silkier, and there's zero buildup (which is huge, because my hair is so fine). I sprinkle it directly on my hair in the shower - the bottle's top is perfect for splashing - starting with the crown of my head, having squeezed most of the water out of my hair. Then I wait a minute and rinse in the coldest water I can stand.
It does indeed smell of vinegar for a bit, but I actually kind of like that - as another reviewer said, it's not a true vinegar scent; it's more herbal and bracing. Even though my hair is pretty porous, it dissipates after a couple of hours. Totally worth it for the shine.