Treating acne (and the discoloration it leaves behind) is no easy task, but the best azelaic acid serums can speed up the process. If you're a skin-care enthusiast, you've likely ...

5. Azelaic Acid How to use it: Azelaic acid can be found in prescription-strength creams as well as a prescription gel. There are also lower-grade options available in over-the-counter serums and ...