If I use a face serum every night, do I also need to apply a moisturizer on top of it?
If you feel your serum isn't hydrating your skin adequately, then consider a moisturizer. But keep in mind that layering the two could cause breakouts, so be cautious. A great, oil-free pick is Lovelyskin Sheer Oil-Free Moisturizer ($35; lovelyskin.com).
Joel Schlessinger, MD, is president of LovelySkin.com and past president of the American Society of Cosmetic Dermatolgy and Aesthetic Surgery.