Azelaic acid is has been shown to even out pigmentation and improve skin tone. However, Dr. Idriss has a major gripe: “when formulated with other ingredients, it’s is often not cosmetically elegant,” she explains (which is why you won’t find it in her skin-care products). “The only one I’ve ever experienced as elegant and non-pilling is prescription, it’s Finacea Gel; I’m not paid by them or endorsed by them. I have found others to have pilled, or smelled weird, or are not a nice texture at all. I’m preaching to be consistent with your skincare to minimize hyperpigmentation, if you’re pilling, no one’s going to want to use it.” Her recommendation with azelaic acid: just use it at night, when pilling might not be a concern.