The Naturium Vitamin C Super Serum Plus ($25) contains a powerhouse combination of vitamin C, retinol, hyaluronic acid, niacinamide, and salicylic acid. I love to use a few drops of this serum morning and night only when I have a hormonal breakout. By the time I have to wash my face, either after a long day or when I wake up in the morning, my skin looks smoother. Although there are a lot of potent ingredients, it's gentle and hydrating to use night and day as long as you wear sunscreen.