When it comes to skincare, it's important to pick a formulation that's suited for your skin. But did you know that the time of application matters, too? In fact, if you apply an ingredient that's meant for the night-time, you can risk reducing its efficacy and even expose your skin to increased sun damage. Here's the lowdown on two of our favourites, vitamin C and retinol, and when exactly you should be applying them. Vitamin C is best used in the morning, as its antioxidant properties help protect your skin against free radicals that can trigger skin ageing. On the other hand, retinol is best used at night, since it can increase your skin's sensitivity to the sun. While these skincare rules aren't necessarily hard and fast – you can use a vitamin C at night and retinol during the day with sunscreen – they're here to keep your skin protected and help you get the maximum benefit from your regimen. If you're ready to get started, here are some of our picks to add to your cart now.