When your color just doesn't look as vibrant and it's time for a touch-up, it's probably the fault of oxidation. And blondes aren't the only ones who get brassy. Oxidation can happen to brunettes and redheads, too. "People think it's the sun that oxidizes, but it's just the elements: hard water in your faucet, shampoo, conditioner," Hill says. "Permanent color, in general, has an expiration date."
At around four weeks when your hair color starts to turn, book a toner, gloss, or buildup remover with your salon (and a conditioning treatment, too). At home, make sure to use a color-correcting shampoo and conditioner — it's not just for blondes. According to Hill, brunettes with ombré hair color and highlights can go brassy, too. The goal is to stay nice and cool, like Margot Robbie pictured here.
