If you have color-treated hair (hi, yes, me), you know that you only have a handful of weeks before your color—blonde or brunette—starts to pick up some unwanted brassy or warm tones. It’s normal.

Welcome to Beauty In A Tik, where each week we put TikTok's viral beauty hacks and innovative trends to the test. Hair toning drops are concentrated serums which include intensely coloured pigment to ...