Paula's Choice 10% Azelaic Acid Booster (£37) is a product that, if you're into skin care, you've probably heard about on social media, as it's gained quite a buzz since it launched in 2018. A lightweight, oil-free cream-gel, it can be used on its own or mixed with a moisturiser or serum. Whilst formulated for all skin types, we'd still recommend starting off slowly, and following it with a simple, hydrating moisturiser.