It makes perfect sense. While your hydrating moisturiser might work well at the beginning of your cycle, when skin tends to be calmer, it could be exacerbating your spots or oiliness at other times, which is why it pays to switch up your routine in response. "Getting to grips with what’s going on with your hormones every month can give you a head start on what to use on your skin to keep it looking youthful and clear," says Charlotte Ferguson, psychotherapist, skin expert and founder of Disciple Skincare . Ahead, she explains exactly which ingredients to incorporate into your routine, and which ones it might be worth avoiding.