Use your azelaic acid product once per day, either in the morning before your sunscreen or at night, before your moisturizer.

Start slowly with this product: it can be irritating, but your skin can adjust to it with time. It is best to start using this product only a few times a week or every other day for the first few weeks. Mild dryness is normal when starting using a retinoid. Once your skin is able to tolerate the product well, you can slowly increase the frequency of use to every day. Make sure to apply a moisturizer regularly when using this product. Apply this product on clean skin, before a moisturizer. Most people prefer using this product at night, but it can be used in the morning as well (once per day in total).