Salicylic acid can be used in either the morning or the evening – just be sure you’re always following up with sunscreen in the morning. This just depends on your skincare routine, and when you’re using other products with potent active ingredients. For example, if you’re using a retinol at night, you’ll need to either apply your salicylic acid in the morning, or alternate between using salicylic acid and retinol every other night.