An oil-soluble exfoliant that gets into pores. At 0.5-2% it is an approved over-the-counter acne ingredient with a modest but real benefit.
Salicylic acid is a beta-hydroxy acid (BHA). Unlike AHAs it dissolves in oil, so it penetrates the sebum in pores and loosens the plug of cells behind blackheads and whiteheads. It is also mildly anti-inflammatory (it is chemically related to aspirin).
In the US it is an approved over-the-counter acne ingredient at 0.5-2%, and at higher strengths it treats dandruff, warts and calluses; clinic peels use 20-30%. In body lotions for rough, bumpy skin it works as a keratolytic, softening thick scale.
It has long clinical use and a place in acne guidelines: the 2024 American Academy of Dermatology guideline gives it a conditional recommendation (lower-certainty evidence), behind benzoyl peroxide and retinoids. A 2020 Cochrane review found only small, low-quality head-to-head trials. Peel studies support benefits for acne and sun damage.
The American Academy of Dermatology's acne guideline makes strong recommendations for benzoyl peroxide, topical retinoids, topical antibiotics and oral doxycycline, and conditional (lower-certainty) recommendations for topical salicylic acid, azelaic acid and clascoterone.
49 trials (3,880 people): azelaic acid is probably less effective than benzoyl peroxide and about as effective as tretinoin for acne; evidence for salicylic acid, nicotinamide and alpha-hydroxy acids was low or very low quality, from small head-to-head trials, and no conclusions were reported for zinc or sulphur.
Reviews salicylic acid toxicity from skin products: salicylism, and even death, can occur from topical use, although it is rare; how much is absorbed depends on the vehicle and conditions of use.
Reviews salicylic acid peels for acne, melasma, photodamage and freckles, including their documented efficacy and safety in both lighter and darker skin types, side effects and salicylism.