The Oribe Bright Blonde Essential Priming Serum (£40) may be spenny, but it's a product we highly recommend adding to your hair regimen if you're not a natural blonde. Inspired by skin-care serums, the multipurpose formula is a hydrator, heat protector, and brass neutraliser in one, as the violet tones and pearlised pigments in the liquid help brighten your blonde and remove any orange tones. And just like a skin-care serum, you can layer multiple other hair products on top of it without it interfering with their efficacy.