15% Azelaic Acid Complex Cream-to-Foam Cleanser Rich Cream Moisturizer Remedy for Dark Spots Intense Hydration Serum Remedy for Dark Circles Can I use this instead of retinol? Azelaic acid works through a different mechanism than retinoids, so it is not a like-for-like swap, but it addresses many of the same concerns. If retinol runs too irritating for your skin, this is a reasonable alternative. Can I use it with Remedy for Dark Spots? Yes, they work well together. If your skin handles actives well, use the azelaic serum AM and PM, applying it first at PM, letting it dry, then following with Dark Spots. If your skin is sensitive, alternate: azelaic in the AM, Dark Spots at PM. When will I see results? Blemishes tend to respond first, around two weeks. Redness around four. Dark spots are slowest, four to eight weeks, and the most worth waiting for. Results compound with continued use. Is there anything it should not be layered with? Avoid using it at the same time as high-strength direct acids, like strong AHA or BHA exfoliants. Everything else layers fine. If you are new to azelaic acid or your skin is reactive, patch test and build frequency slowly. What testing has this been through? The serum reduced tyrosinase gene expression by 65.2% and kallikrein-5 by 39.5%, both versus exposed controls. Tyrosinase is the enzyme behind melanin where dark spots begin. KLK5 is the protease behind inflammation where redness begins.