Lactic acid is already present in your skin as part of your NMF (natural moisturising factor) and is one of the best acids to incorporate into your routine thanks to its ability to exfoliate and hydrate at the same time. "It's a larger molecule than glycolic, which means that while it takes a little longer to penetrate, the skin has a moment to adjust to the drop in pH so you get all the great exfoliating benefits but without the redness and inflammation," David Delport, Ren Clean Skincare's global brand ambassador, told POPSUGAR. After cleansing, use a cotton pad and sweep the Ren Clean Skincare Ready Steady Glow Daily AHA Tonic (£27) over your skin to gently exfoliate and brighten your complexion without any irritation. You might feel a slight tingling the first couple of times you use it, but we promise this is one of the gentlest chemical exfoliants on the market.