Tretinoin / Benzoyl peroxide works through the following mechanisms:
Anti-inflammatory activity
Tretinoin reduces inflammation in the skin.
Antibacterial activity
Benzoyl peroxide kills acne bacteria (C. acnes).
Anti-keratinization activity
Tretinoin and benzoyl peroxide reduce the production of keratin (a sticky skin protein), which helps skin cells shed from the skin. This helps clear and prevent clogged pores.