The other thing to remember here (I promise the science lesson will be over soon) is stability. Vitamin C is an amazing antioxidant with wonderful skincare benefits. It’s also about as stable as a first-day Love Island relationship when a new hottie enters the villa. It’s hard enough getting it into a serum or lotion and maintaining the efficacy, let alone putting it into a cosmetic product. Rowan and I were in agreement: "Skincare and makeup are probably best kept separate. I understand the appeal of multitasking products but in reality, the concentrations of the ingredients and the formulation mean that any pollution-proofing claims are going to be very flimsy."