Salicylic Acid vs Benzoyl Peroxide: Which Is Better for Acne?

If your acne is mostly blackheads and whiteheads, salicylic acid is the better-targeted choice; if it’s mostly red, inflamed pimples, benzoyl peroxide has more going for it, including much stronger evidence. They work in different ways, so plenty of routines use both. The catch is that using both is more drying, so it’s worth knowing what each one actually does before you stack them.

What’s the difference between salicylic acid and benzoyl peroxide?

They’re both over-the-counter (OTC) acne drugs in the US, but they go after different parts of the acne process.

Salicylic acid is a beta hydroxy acid (BHA), an exfoliant. According to DermNet, it “helps slow down shedding of the cells inside the follicles, preventing clogging.” In other words, it works on the plug of dead skin cells and oil that becomes a blackhead or whitehead. The FDA’s acne monograph allows it in OTC products at 0.5 to 2 percent.

Benzoyl peroxide is mainly an antimicrobial. StatPearls (NCBI Bookshelf) describes it as having “bactericidal effects against Cutibacterium acnes,” the bacterium involved in inflamed acne, plus mild peeling (keratolytic) effects. Importantly, the same review notes that “drug resistance has not appeared to develop with benzoyl peroxide use,” which is why it’s often paired with antibiotics. OTC products can contain 2.5 to 10 percent.

A simple way to remember it: salicylic acid mainly unclogs; benzoyl peroxide mainly kills bacteria and calms inflamed spots. If you want more detail on either one, see my full guides to salicylic acid for acne and benzoyl peroxide for acne.

Which one has better evidence?

Benzoyl peroxide, clearly. The 2024 American Academy of Dermatology (AAD) acne guideline gives benzoyl peroxide a strong recommendation and salicylic acid only a conditional one. As MDedge reported, the salicylic acid recommendation rests on a single randomized controlled trial with evidence rated low certainty, and the guideline authors said the evidence was insufficient to compare it directly with other topicals.

Benzoyl peroxide has been studied far more, though not always well. A 2020 Cochrane review pooled 120 trials. It found benzoyl peroxide “may be more effective than placebo or no treatment” and that there “may be little to no difference” between it and the prescription-strength retinoid adapalene. The reviewers rated the certainty of the key evidence as low, largely because of how the trials were run and reported. So “strong recommendation” doesn’t mean “perfect evidence”; it means guideline experts are confident enough to recommend it for most people.

What about head-to-head trials? There’s very little. A 2020 Cochrane review of salicylic acid and other topicals found that the trials comparing salicylic acid with benzoyl peroxide didn’t measure physician-rated overall improvement, and the only side-effect data came from one 41-person study rated very low certainty. The most-quoted direct comparison is a 1989 crossover study of 30 patients that compared a 2% salicylic acid cleanser with a 10% benzoyl peroxide wash over four weeks; only the salicylic acid cleanser significantly reduced comedones (blackheads and whiteheads). That fits with how the two ingredients work, but a two-week-per-arm study of 30 people from 1989 is a thin basis for any strong claim.

Salicylic acid vs benzoyl peroxide: side-by-side comparison

Which should you use for your type of acne?

Match the ingredient to the spots you actually have. (Not sure which you have? My guide to blackheads vs whiteheads can help.)

• Mostly blackheads and whiteheads: the AAD says that because salicylic acid “unclogs pores and exfoliates the skin,” it “works best on whiteheads and blackheads.” A topical retinoid such as adapalene is another option with stronger evidence for clogged pores.
• Mostly red bumps and pus-filled pimples: the AAD calls benzoyl peroxide “especially effective at treating mild pimples.”
• A mix of both (the most common situation): the AAD guideline recommends “using topical therapies combining multiple mechanisms of action.” That’s the logic behind pairing an unclogger with an antibacterial.
• If you’ve been prescribed an antibiotic: the guideline recommends combining antibiotics with benzoyl peroxide, which helps limit antibiotic resistance. Salicylic acid doesn’t do this job.
• Deep, painful nodules or cysts: neither is enough on its own. The AAD notes these lesions “often cause permanent acne scars” and need a dermatologist.

What strength should you choose?

For benzoyl peroxide, stronger isn’t necessarily better. The AAD advises that while products go up to 10%, “it’s best to start with a product that contains 2.5%.” That advice has some trial support: in three double-blind studies in 153 patients (1986), 2.5% benzoyl peroxide was as effective as 5% and 10% at reducing inflamed lesions, and caused less peeling, redness and burning in at least some of the comparisons. It was one older set of studies, but it’s a useful reason to start low.

For salicylic acid, OTC products top out at 2%. I couldn’t find good head-to-head evidence showing that one strength within the 0.5% to 2% range is clearly better than another. Many people start with a wash and move to a leave-on product if they tolerate it.

Can you use salicylic acid and benzoyl peroxide together?

Yes, and many people do, but expect more dryness. The FDA-required label on OTC acne products warns that “skin irritation and dryness is more likely to occur if you use another topical acne medication at the same time.” Some practical ways to combine them without wrecking your skin barrier:

• Use one as a wash and one as a leave-on. For example, a salicylic acid cleanser plus a thin layer of 2.5% benzoyl peroxide gel.
• Or alternate. Salicylic acid in the morning and benzoyl peroxide at night (or on alternate days) spreads out the irritation.
• Add one product at a time. Give your skin a couple of weeks to adjust before adding the second.
• Moisturize. A plain, non-comedogenic moisturizer helps you stick with drying treatments. My simple acne routine shows where each step fits.

A note on retinoids: StatPearls notes that adapalene is compatible with benzoyl peroxide, and a 2019 systematic review concluded retinoids “should be used in combination with benzoyl peroxide to optimize results.” But the same StatPearls review advises against applying benzoyl peroxide at the same time as tretinoin, because it can reduce tretinoin’s effectiveness. The tretinoin prescribing information also advises caution with products containing salicylic acid. If you use prescription tretinoin, ask your prescriber how to fit either OTC ingredient in.

Side effects and who should be careful

Benzoyl peroxide: the most common problems are dryness, redness and scaling, especially at higher strengths. StatPearls calls its bleaching quality its most common adverse effect, and the FDA label warning says to “avoid contact with hair and dyed fabrics, which may be bleached.” Use white towels and pillowcases. A small percentage of people develop contact dermatitis (an allergic-type rash).

Salicylic acid: DermNet notes mild stinging, especially on broken skin. Because it’s absorbed through skin, very heavy use can rarely cause salicylate poisoning; warning signs include confusion, nausea, rapid breathing and ringing in the ears. DermNet also says salicylic acid preparations shouldn’t normally be used in children under 2.

Both: in 2014 the FDA warned that OTC acne products containing either ingredient can, rarely, cause serious allergic reactions. It identified 131 cases between 1969 and January 2013, and 44% needed hospitalization. The FDA suggests applying a new product to one or two small areas for 3 days first. Throat tightness, trouble breathing, feeling faint, or swelling of the face, eyes, lips or tongue are an emergency.

What about pregnancy?

Both are generally considered lower-risk options. The AAD says salicylic acid “is generally considered safe when used for a limited time” and that experts consider benzoyl peroxide “safe to use in limited amounts.” The MotherToBaby fact sheet notes that the American College of Obstetricians and Gynecologists lists benzoyl peroxide and salicylic acid among OTC ingredients that may be used in pregnancy if needed. Still, check with your obstetrician or dermatologist before starting anything new.

Frequently asked questions