Salicylic acid
Salicylic acid (BHA): conditionally recommended for acne in the AAD 2024 guideline; oil and pore evidence is limited (no placebo-controlled trial).
What it is
Salicylic acid is a beta hydroxy acid (BHA). It is oil-soluble and is used in cleansers, toners, gels and serums aimed at breakouts and oily skin. Korea's Ministry of Food and Drug Safety (MFDS) lists it as a notified acne-relief ingredient for rinse-off products.
Evidence grades by concern
| Concern | Grade | Citations |
|---|---|---|
| Comedonal acne | B | Liu 2025, Reynolds 2024 |
| Inflammatory acne | B | Li 2023, Reynolds 2024 |
| Excess sebum | C | Liu 2025 |
| Enlarged pores / blackheads | C | Li 2023 |
Grade A: strong guideline recommendations or Korean MFDS notified actives. B: randomized controlled trials or systematic reviews. C: mechanism, small or uncontrolled studies.
What the evidence shows
The American Academy of Dermatology's 2024 acne guideline gives topical salicylic acid a conditional recommendation, not a strong one; its strong recommendations go to benzoyl peroxide, topical retinoids and topical antibiotics (Reynolds 2024). The two trials below both tested multi-ingredient products and had no placebo or vehicle group, so they show change from the start of treatment, not an effect beyond what an inactive product would have done.
Comedonal acneB
In a 21-day study of 42 people with mild-to-moderate acne and oily or combination skin, a salicylic acid gel used twice daily was followed by a 23.65% fall in sebum and a 23.81% improvement in the acne severity score (Liu 2025). The study had a single group and did not count blackheads or whiteheads separately. The serum trial described below did report fewer closed and open comedones after 8 weeks (Li 2023). The AAD guideline's recommendation is conditional (Reynolds 2024).
Inflammatory acneB
In an 8-week randomized trial of 83 adults with comedones and post-acne marks, people used a serum containing salicylic acid and lipohydroxy acid (LHA), either alone or with a mask. In both groups acne severity, comedones, sebum and post-acne redness and pigmentation improved significantly from baseline; adding the mask improved acne severity and closed comedones more than the serum alone (Li 2023). Randomization compared the mask with no mask, so every participant used salicylic acid and the trial cannot separate its effect from LHA or from time. The AAD guideline's recommendation is conditional (Reynolds 2024).
Excess sebumC
The evidence is limited. In the 21-day gel study above, sebum fell by 23.65% from baseline, measured with a sebumeter (Liu 2025), but there was no comparison group, so the fall cannot be attributed to salicylic acid. No guideline recommendation covers oily skin.
Enlarged pores / blackheadsC
The evidence is limited. In the 8-week serum trial above, the density of skin pores improved from baseline in both groups (Li 2023), but every participant used the same salicylic acid and LHA serum and there was no group without it, so the change cannot be attributed to salicylic acid alone.
What it does not do
Salicylic acid is not one of the AAD guideline's strongly recommended acne treatments. Neither trial compared it with a placebo, and both tested products that contained other ingredients, so the size of its own effect is not known. The trials lasted 3 and 8 weeks; they do not show what happens over months of use. The pore result is a change from baseline, not evidence that pores shrink permanently.
Safety
- Cosmetic Ingredient Review (CIR) Expert Panel conclusion: safe with qualifications (report year 2025; IJT 44(S4):5-57, amended report).
- CIR qualifications: formulated to be non-irritating, with caution about increased sun sensitivity.
- EU Cosmetics Regulation, Annex III: Rinse-off hair products 3%; other products including leave-on 2%; body lotion, eye shadow, mascara, eyeliner, lipstick and roll-on deodorant 0.5%; not for products for children under 3 (Reg (EU) 2019/1966, Annex III/98)
- Korea (MFDS) notified acne relief ingredient: 0.5% (rinse-off products)
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References
- Liu Y, Dan Y, Yang J, et al. Clinical Efficacy of a Salicylic Acid-Containing Gel on Acne Management and Skin Barrier Function: A 21-Day Prospective Study. J Cosmet Dermatol. 2025;24(7):e70353.
- Li S, He X, Zhang Z, et al. Efficacy and safety of a facial serum and a mask containing salicylic acid and lipohydroxy acid in acne management: A randomized controlled trial. J Cosmet Dermatol. 2023;22(9):2502-2511.
- Reynolds RV, Yeung H, Cheng CE, et al. Guidelines of care for the management of acne vulgaris. J Am Acad Dermatol. 2024;90(5):1006.e1-1006.e30.