From the brand that makes our favourite sustainable shower filter is a new scalp treatment aimed at balancing the scalp's pH level. A little biology lesson: your scalp is naturally slightly acidic, and when the scalp's pH becomes more alkaline due to things like hard water, shampoos, and styling products, the skin is therefore more prone to irritation. The Hello Klean Clarifying Scalp Soak (£25), which launches on Cult Beauty on 23 March, has been formulated with an acidic base pH of 4.0, so not only does it gently break down product build-up and wash away excess oils with the help of apple cider vinegar and phytic acid, but it also helps restore your scalp to its natural pH level