Prebiotics & Niacinamide Pore Refining BoosterPore size is genetic, but you can ensure yours are healthy and smooth with this high strength booster serum for all skin. Niacinamide is paired with 12 other pore refiners and brighteners to provide comprehensive treatment of many conditions that often plague acneic skin. Licorice root supports a more even skin tone, while the prebiotic and probiotic complex promotes a strengthened barrier and less sensitivity.