Benzoyl peroxide kills the germs that cause acne and can help dry up oily skin. It is also a mild exfoliant and can clear your pores of acne-causing debris like dirt. If you have severe acne ...

According to dermatologist Shari Marchbein, M.D., mixing skincare ingredients—like benzoyl peroxide with retinol—without knowing how they'll interact isn't a good idea. "[It] will be not only ...