How long should I let azelaic acid sit before moisturizer? This seemingly simple question often perplexes many individuals venturing into the realm of skincare. When it comes to layering products, especially potent actives like azelaic acid, one must consider several nuanced factors. Is there an optimal duration for allowing the azelaic acid to adequately absorb into the skin before applying a moisturizer? Furthermore, does the formulation of the moisturizer play a pivotal role in the timing? If one were to apply a heavier, more occlusive moisturizer, would that necessitate a longer waiting period? Additionally, how do skin types and conditions—such as oily, dry, or acne-prone skin—influence this crucial decision? Are there particular signs or sensations one should be mindful of to determine if absorption has occurred? These questions tantalize the mind and warrant further exploration into an effective skincare regimen.