When it comes to over-the-counter acne treatments, benzoyl peroxide and salicylic acid are the two most popular active ingredients. They’re both effective, but they work in completely different ways and are suited to different types of acne.
Benzoyl Peroxide
This powerful ingredient kills acne-causing bacteria (C. acnes) on contact. Unlike antibiotics, bacteria don’t develop resistance to benzoyl peroxide, making it a reliable long-term treatment. It also has mild comedolytic properties, meaning it helps prevent clogged pores.
Best for: inflammatory acne (red, tender, pus-filled pimples). Available in concentrations from 2.5% to 10%. Studies show 2.5% is just as effective as higher concentrations with significantly less irritation.
Salicylic Acid
A beta hydroxy acid (BHA) that’s oil-soluble, allowing it to penetrate into pores and dissolve the mixture of sebum and dead skin cells that causes blackheads and whiteheads. It also has anti-inflammatory properties.
Best for: comedonal acne (blackheads and whiteheads), enlarged pores, and oily skin. Available in 0.5% to 2% concentrations in cleansers, toners, and spot treatments.
Can You Use Both?
Yes, but not at the same time. A common approach is to use a salicylic acid cleanser in the morning and benzoyl peroxide as a spot treatment in the evening. Start slowly and watch for signs of over-drying or irritation.
The Bottom Line
If your acne is mostly blackheads and whiteheads, salicylic acid should be your first choice. If you have inflamed, red pimples, benzoyl peroxide is more appropriate. Many people benefit from using both as part of a comprehensive routine.