Salicylic Acid for Acne: How It Works and What the Evidence Says

Salicylic acid is a mild, oil-soluble exfoliant that helps unclog pores, which makes it most useful for blackheads and whiteheads. It’s sold without a prescription at 0.5% to 2%, it’s gentle enough for most people, and the American Academy of Dermatology (AAD) does recommend it. But the research behind it is thinner than its reputation suggests, so it works best as a supporting player rather than the star of a routine.

What is salicylic acid?

Salicylic acid is a beta hydroxy acid (BHA), a close chemical relative of aspirin. In the US, it is one of only a handful of active ingredients allowed in over-the-counter (OTC) acne drugs under the FDA’s acne monograph, which permits salicylic acid at 0.5 to 2 percent. You’ll find it in cleansers, toners, pads, gels and leave-on treatments, and the percentage should be printed in the Drug Facts box on the label.

You may also see much stronger salicylic acid mentioned online. DermNet notes that salicylic acid preparations range from 0.5% up to 30% depending on what they’re used for, and the 30% end is used for in-clinic chemical peels, not everyday acne care.

How does salicylic acid work on acne?

Acne starts when dead skin cells and oil (sebum) clog a hair follicle. Salicylic acid targets that first step. According to DermNet, topical salicylic acid “helps slow down shedding of the cells inside the follicles, preventing clogging,” and helps break down existing blackheads and whiteheads.

What makes it different from water-soluble exfoliants like glycolic acid is that it’s lipid-soluble. A 2015 review in Clinical, Cosmetic and Investigational Dermatology explains that salicylic acid mixes with the oily lipids inside hair follicles, which is why it can work inside the pore rather than just on the surface. The same review describes it as desmolytic (it loosens the “glue” between skin cells rather than dissolving keratin itself), comedolytic, and mildly anti-inflammatory.

Salicylic acid’s main job is unclogging. It isn’t primarily an antibacterial, whereas benzoyl peroxide is described by StatPearls as bactericidal against the acne bacterium Cutibacterium acnes. That difference is one reason the two are often paired. I compare them head to head in salicylic acid vs benzoyl peroxide.

What does the evidence actually show?

This is where honesty matters. The 2024 AAD acne guideline (Reynolds et al., JAAD) gives salicylic acid a conditional recommendation, while benzoyl peroxide, topical retinoids and topical antibiotics get strong recommendations. As MDedge’s coverage of the guideline reported, the salicylic acid recommendation rests on a single randomized controlled trial, and the certainty of that evidence was rated low.

In plain English: salicylic acid probably helps, especially for clogged pores, but we don’t have the large, high-quality trials that exist for retinoids and benzoyl peroxide. The UK’s NICE-based treatment pathway, as summarized by NHS Scotland’s Right Decisions acne pathway, doesn’t list salicylic acid among its first-line options at all. Those options are built around adapalene, benzoyl peroxide, clindamycin, tretinoin and azelaic acid.

Where dermatology organizations do agree is on its best use. The AAD’s patient guide to adult acne says that because salicylic acid “unclogs pores and exfoliates the skin,” it “works best on whiteheads and blackheads.” The AAD’s treatment overview says it’s “effective for treating whiteheads and pimples.” For red, inflamed or deep spots, it’s usually not enough on its own.

How to use salicylic acid for acne

The FDA’s monograph directions for OTC acne products are a sensible template. They tell users to “cover the entire affected area with a thin layer one to three times daily” and to start with one application a day, increasing gradually if your skin tolerates it. A few practical points:

• Pick one salicylic acid product, not three. A cleanser, toner and spot gel all containing BHA is an easy way to over-dry your skin. The monograph labeling itself warns that irritation and dryness are more likely if you use another topical acne medication at the same time.
• Leave-on beats rinse-off for contact time. A cleanser is on your face for seconds; a leave-on gel or toner stays in contact longer. Either can fit a routine, but if a wash isn’t doing anything after a couple of months, that may be why.
• Patch-test first. The FDA advises applying a new OTC acne product to one or two small affected areas for 3 days before using it more widely.
• Moisturize and wear sunscreen. Exfoliation can leave skin drier and more reactive. My guide to moisturizer and sunscreen for acne covers non-clogging options.
• Be patient. The AAD says to give a treatment six to eight weeks before deciding whether it works.

If you’re building a routine from scratch, salicylic acid fits well as the cleanser step in a simple acne routine, alongside a guideline-backed leave-on treatment such as adapalene.

Side effects and who should be careful

For most people, the main downside is irritation. DermNet notes that mild stinging can occur, especially on broken skin or with higher concentrations, and that salicylic acid can irritate or burn healthy skin. Dryness and peeling are common if you overdo it.

Two rarer risks are worth knowing about:

• Serious allergic reactions. In 2014 the FDA warned that OTC acne products containing benzoyl peroxide or salicylic acid can, rarely, cause serious hypersensitivity reactions. It identified 131 cases between 1969 and January 2013, 44% of which required hospitalization. Symptoms such as throat tightness, trouble breathing, feeling faint, or swelling of the face, eyes, lips or tongue need emergency care. These are different from ordinary redness, dryness and peeling.
• Salicylate toxicity (salicylism). Because salicylic acid can be absorbed through skin, heavy use over large areas can, very rarely, cause aspirin-like poisoning. The 2015 review calls systemic toxicity from skin absorption “a very rare phenomenon” but “a serious concern.” MedlinePlus lists warning signs including confusion, dizziness, rapid breathing, ringing in the ears or hearing loss, nausea, vomiting and diarrhea.

MedlinePlus also advises that children and teenagers who have chickenpox or the flu should not use topical salicylic acid unless a doctor says to, because of the risk of Reye’s syndrome, and to check with a doctor before combining it with other acne treatments or aspirin-containing products. DermNet says salicylic acid preparations shouldn’t normally be used in children under 2.

Is salicylic acid safe during pregnancy?

Low-strength topical salicylic acid is generally considered acceptable, with caveats. The AAD’s pregnancy page says salicylic acid “is generally considered safe when used for a limited time,” and recommends checking with your doctor first. The MotherToBaby fact sheet (October 2023) notes that the American College of Obstetricians and Gynecologists lists salicylic acid among the topical acne options that may be used in pregnancy, and that only a small amount of topical acne medication is likely to be absorbed.

High-strength salicylic acid peels are a different story. The 2015 peel review says salicylic acid peels are not recommended during pregnancy because of the chemical’s close relationship to aspirin. If you’re pregnant or trying to conceive, stick to low-strength OTC products on limited areas, skip the peels, and run your routine past your obstetrician or dermatologist.

Salicylic acid vs other acne ingredients

If you only have blackheads and whiteheads, salicylic acid is a reasonable, inexpensive first try. If you have inflamed pimples, benzoyl peroxide and topical retinoids have much stronger evidence. The AAD guideline also emphasizes combining treatments that work in different ways, and salicylic acid mainly targets one of acne’s causes (clogged pores). Adapalene also targets clogging but has stronger evidence behind it; see adapalene (Differin) for how it compares.

Frequently asked questions