7 Ways You're Accidentally Turning Your Blond Hair Yellow Or Brassy

There are certain beauty lessons we all know: Dirty makeup brushes can cause breakouts, retinols and sunbathing don't mix, mascara needs to be replaced regularly, and so on. But the proper care and maintenance of blond hair can be particularly elusive. Why? Because blond hair is so damn difficult to take care of.

One of the most common issues? Unwanted brassy and yellow tones. Luckily, you don't need a PhD in chemistry to learn how to keep the colour from veering into that territory. For the CliffsNotes, we consulted two colour experts: Riawna Capri, owner of L.A.’s Nine Zero One Salon and hairstylist to stars like Julianne Hough and Nina Dobrev, and Joico celebrity colourist Denis De Souza, who’s worked with the likes of Olivia Wilde, Kate Mara, and Jenna Dewan.

“Champagne blondes look more expensive and more natural," Capri tells us. "When your hair is yellow and brassy it looks cheap, like you haven’t been taking care of it — and it might not be your fault!”

Why is blonde hair so prone to discolouration? There are two main reasons. First, understand that rarely is hair lightened to the exact shade that’s desired. Instead, once hair is bleached out, it must then be treated with a toner to create the sought-after shade. Capri explains it like this: Hair colour is like leggings, and toner is like stockings. Since the toner your colourist applies is super-sheer, it can wear off quickly, leaving unwanted hues behind. That is, unless it's cared for properly.

Second reason: “Because blond hair tends to be more porous, it ends up discolouring over time,” De Souza says. Which means it's soaking up things that are messing with your blond, like water and products. However, armed with the right knowledge and tools, you can keep your blond from going bad.

Click through for the top seven common discolouration culprits to avoid.