What Is Benzoyl Peroxide? 2 Dermatologists Break Down the Acne-Fighting Ingredient

When it comes to over-the-counter treatments, acne responds best to two ingredients: benzoyl peroxide and salicylic acid. While salicylic acid is fairly well-known and celebrated, its acne-fighting counterpart benzoyl peroxide shouldn't be underestimated. The thing is, benzoyl peroxide is already utilised in a ton of skin-care products, from cleansers to spot treatments — you just may not know you're using it.

But what is benzoyl peroxide? And how exactly does it help with acne? It's not magic, but it's pretty close. While it may be tempting to combine the powers of benzoyl peroxide with salicylic acid, the two treat acne differently. To help you understand more about the ingredient and how to use it to help with breakouts, keep reading.

What Is Benzoyl Peroxide?

Benzoyl peroxide attacks acne-causing bacteria in your pores to treat existing pimples and prevent new ones. It can be found in over-the-counter formulations and prescriptions. "Benzoyl peroxide is highly lipophilic, which allows the molecules to penetrate the skin surface and target the hair follicle," Ted Lain, MD, board-certified dermatologist and chief medical officer at Sanova Dermatology, told POPSUGAR. Its primary benefit is not exfoliation, but it does help with that as a secondary gain.

Who Should Use Benzoyl Peroxide?

This ingredient works best on acne caused by bacteria like inflammatory pimples, which include pustules, papules, nodules, and cysts. Dr. Lain explained it's "those with predominantly pus bumps and pimples." With that in mind, it's not the preferred ingredient for treating blackheads and whiteheads. Those with sensitive or dry skin should also be careful using benzoyl peroxide as it can aggravate skin.

The Downside to Using Benzoyl Peroxide

Benzoyl peroxide is a powerful ingredient, and while it's effective at treating mild to moderate acne cases, you should check with your dermatologist first before incorporating it into your skin-care routine. "It doesn't only kill p.acnes bacteria, it also kills good bacteria," said Dennis Gross, MD, board-certified dermatologist and founder of Dr. Dennis Gross Skincare. "Benzoyl peroxide is a free radical and actually damages skin while it clears acne. That means it injures normal skin cells and can create dryness, redness, and irritation."

In general, overdoing it with any active ingredient, including benzoyl peroxide, can damage the skin's barrier. "When you strip the skin's moisture barrier, you can actually make breakouts worse," Dr. Gross said. If you're unsure if benzoyl peroxide is a good ingredient for you to use, consult with a skin-care expert like a dermatologist, and always start slow and do a patch test.