Acne treatments: The difference between salicylic acid and benzoyl peroxide

I’m in a very geeky-Thursday mood. Well, it actually started when a friend of mine and I were talking recently about acne treatments and somehow (attempted) to get into the nitty-gritty about the difference between two common ingredients found in acne-fighting products: salicylic acid and benzoyl peroxide. I’m sure many of you are at least familiar with the names from the noted active ingredients in your face wash or similar products. But what’s the difference between them? How would you know when to use one over the other?

I asked, Dr. Mona A. Gohara, assistant clinical professor of the department of dermatology at Yale’s School of Medicine (who also helped us figure out our summer dry skin woes), to give us some more insight on the two ingredients:

Is there a big difference in the chemical composition of the two?
Benzoyl peroxide (BP) and salicylic acid (SA), combat acne in different ways. BP
is an antibiotic which helps to reduce the amount of bacteria loitering in your
skin’s oil glands. SA is an acid that helps to exfoliate the skin, unclogging
pores so that whiteheads and blackheads are less likely to form.

When would you recommend people use a product with benzoyl and when with salicylic?
I recommend that people use them in tandem — you get more bang for your buck and
are attacking acne from different angles. Often I recommend to patients that
they use a BP wash everyday in the shower. I will have them substitute a SA
wash on one of those days. Or, I will have them use the washes on alternate
days depending how sensitive their skin is.

Is one harsher than the other?
Both products can be irritating, leaving the skin red, flaky, and dry. That’s why
moisturization with non-comedogenic lotions/creams is paramount!

Are they both used for acne or do they have any other indications?

BP is used primarily for acne, but can also be used for folliculitis (pimples on the legs, groin, or buttocks). SA is also used in the treatment of psoriasis, a skin condition called keratosis pilaris (bumpy skin on the upper outer arms), and for rejuvenation.

What are some of your favorite products with benzoyl peroxide? With salicylic?
Neutrogena Body Clear Body Wash, Salicylic Acid Acne Treatment
Aveeno Daily Clear Complexion, Cleansing Pads, with SA and soy (helps discoloration that results from old pimples)
Neutrogena Oil-Free Acne Wash, Pink Grapefruit
Johnson and Johnson Clean & Clear Continuous Control Acne Cleanser

And, remember, benzoyl peroxide washes can bleach your towels or clothes (those of you who use ProActiv might be familiar with this), so be careful.

What are some of your favorite acne treatments? Does you use mostly salicylic acid or benzoyl peroxide products?