Contains 5% Benzoyl Peroxide (BPO) - a very effective antibacterial lotion for the treatment of acne and acne-prone skin. This micronized benzoyl peroxide solution assists by killing acne causing bacteria (p. acnes bacteria) and helping to clear dead skin and oil from pores. Jan Marini Skin Research uses ultra-micronized BPO to get even greater penetration into the skin while minimizing sensitivity and irritation common with many benzoyl peroxide solutions.