Vitamin C serum can be used either in the morning or night and even twice a day. , If you apply retinol at night, then use vitamin C serum in the morning. If you only use a moisturiser at night, then Can Vitamin C Serum Cause Pimples? Read Before Use! Vitamin C for Glowing Skin: Benefits & Best Ways to Use It Indulgeo Essentials Vitamin C on Lips Before After TikTok The best vitamin C serums in the UK for every skin type and budget, tested Skincare The Guardian