Allies of Skin is known for its efficient formulations, and the Allies of Skin Prebiotics and Niacinamide Pore-Refining Booster (£65) is the brand's latest addition. The trifecta of niacinamide, probiotics, and prebiotics aims to brighten and strengthen the skin while restoring the all-important skin barrier. Either mix it into serums, moisturisers, or masks, or apply it directly to skin after cleansing.