Salicylic Acid
Salicylic acid rates Clear, but the rating is a judgement rather than a reading: we identified no comedogenicity assay of it in the numeric papers we hold, and the only salicylate in Fulton's table is octyl salicylate, a sunscreen ester — a different molecule doing a different job. What it has instead is a clinical guideline that recommends applying it to acne-prone skin, because it is comedolytic. The ingredient people paste into a pore-clogging checker is the one dermatologists use to clear the clogs.
AAD 2024 conditionally recommends it for acne. Comedolytic, which is the opposite of clogging.
What it is
Salicylic acid is a beta hydroxy acid — a benzene ring carrying a hydroxyl group and a carboxylic acid group. Its formula is C7H6O3 and its molecular weight is about 138 g/mol. The carboxylic acid makes it acidic; the aromatic ring makes it lipophilic, which is the property that matters here, because an oil-soluble acid can move into the sebum-filled follicle rather than sit on the surface. In skincare it is used as a keratolytic and comedolytic exfoliant. On a label it is Salicylic Acid, and it is marketed as "BHA." Four near neighbours share the salicylate name and are not this material, which is the whole reason the identity section below matters. Octyl salicylate — also called ethylhexyl salicylate or octisalate — is a UVB sunscreen filter, C15H22O3, an ester of salicylic acid with 2-ethylhexanol and not an acid at all. Sodium salicylate is the sodium salt. Acetylsalicylic acid is aspirin. Salix Alba (willow) bark extract contains salicin, a glycoside that is not free salicylic acid. Nothing on this page transfers between them.
Why we rate it Clear
We rate salicylic acid Clear at Moderate confidence. Clear here is an editorial risk classification, not a measured pass, and the Moderate rests on a named clinical recommendation rather than on a comedogenicity assay, because no comedogenicity assay of salicylic acid is something we could find. Start with the absence, because it is half the story and it is the more surprising half. We identified no comedogenicity assay of salicylic acid in the numeric papers we hold. Fulton's 1989 rabbit-ear table, the source of most of the comedogenic numbers now in circulation, has no salicylic acid row; we read its 220 rows off a 400dpi render. It does contain exactly one salicylate: "Octyl salicylate," scored 0, sitting in the paper's sunscreen block just after octyl methoxycinnamate. That is 2-ethylhexyl salicylate — octisalate, the UVB filter — a different molecule (C15H22O3 against C7H6O3) doing a different job. A reader who reads "salicylate, 0" off that row is reading a sunscreen ester's score, not this acid's, and the matching word is the only thing the two share. Morris and Kwan's 1983 assay, an independent laboratory on the same 0-5 scale, tested seven lanolins, nine vegetable oils, eleven esters and five surfactants; salicylic acid is not among the 32. Fulton, Pay and Fulton's 1984 rabbit-ear paper has no salicylic acid row. Nguyen, Dang and Maibach's 2007 study names its fourteen test materials in its abstract and salicylic acid is not one of them. So the 0 that consumer checkers print for salicylic acid is not a measurement we can trace to any primary assay. What salicylic acid has instead — and what almost nothing else on the unassayed list has — is a clinical guideline pointing the reassuring way. The American Academy of Dermatology's 2024 acne guideline (Reynolds and colleagues) conditionally recommends topical salicylic acid for acne. That is a recommendation to apply the ingredient to exactly the skin most likely to react to a pore-clogger, and it is checkable, unlike an unsourced 0. It is a proxy and not a comedogenicity measurement, and its own limits are worth stating: the guideline records the recommendation as conditional rather than strong. The mechanism runs the same direction. Salicylic acid is a keratolytic and desmolytic agent: it loosens the junctions between corneocytes and, being lipophilic, penetrates the follicle, so its documented action is to clear a comedo rather than to form one (Arif 2015). Moderate, not High, is the deliberate call, because a High would require a comedone count and we found none — what there is, is a clinical recommendation to use it on acne and a mechanism that points away from clogging.
What the evidence doesn’t tell you
This rating is built on an absence plus a proxy, and neither is a comedone count. We identified no rabbit-ear assay of salicylic acid, no human comedone-induction study, no cyanoacrylate follicular biopsy — in either direction. An audit can establish that no assay turned up in the papers we hold and the searches we ran; it cannot establish that none was ever run anywhere. If one were run tomorrow we would have no standing to be surprised by the result whichever way it fell. The AAD recommendation is the firmest thing on this page and it answers a different question. It is a treatment recommendation — does salicylic acid help acne — not a comedogenicity test, and the guideline records it as conditional. A material can in principle improve acne overall and still do something on a separate endpoint; the mechanism argues against that here, but a mechanism is reasoning, not a result. The keratolytic and comedolytic data describe what salicylic acid does to keratin and to existing comedones; they are not a measurement that the acid cannot itself provoke a follicular reaction at some concentration. Salicylic acid is an acid, and irritation at higher strengths is real — but irritation and a comedone are different lesions, and neither of the two should be read as the other. There is no dose-response comedogenic information of any kind: no comedogenic number attaches to any concentration, and salicylic acid is used across a wide range, from the 0.5% to 2% the AAD guideline records for the OTC form up to in-office peel strengths we hold no sourced figure for, so where it sits on an ingredient list tells a reader nothing. Finally, the near-miss deserves its own caution: octyl salicylate's 0 is a genuine, reassuring reading, but it is a reading about a sunscreen ester, and a shared word is not a shared measurement. Beyond this ingredient, a 2025 review of the field reports that no standardised comedogenicity test exists and that "non-comedogenic" is an unregulated label.
Where you’ll see it
On a label it appears as Salicylic Acid. In over-the-counter acne products it is used at 0.5% to 2%, the range the AAD guideline gives for the OTC form — cleansers, toners, pads, spot treatments and leave-on serums. In-office chemical peels are a clinical procedure rather than a cosmetic use and work at higher strengths, for which we hold no sourced figure. The concentration therefore varies widely across its uses, and none of those numbers is a comedogenicity figure. Its salicylate neighbours turn up on labels too, and are separate ingredients: Ethylhexyl Salicylate (octisalate) in sunscreens, Salix Alba (Willow) Bark Extract in "natural" formulas, and sodium salicylate or betaine salicylate, which are separate materials carrying no evidence that transfers from this page. Where salicylic acid sits in an ingredient list is not a comedogenicity signal, and there is no measured number to read off it in any case.
Sources
Each source says what it actually is. Several widely-cited “sources” for comedogenic ratings are republishing the same 1989 assay, and counting them as independent agreement is how a thin evidence base gets made to look thick.
- Fulton JE. "Comedogenicity and irritancy of commonly used ingredients in skin care products." J Soc Cosmet Chem 40:321-333 (1989) The rabbit-ear survey most online comedogenic numbers descend from. Method: ingredient diluted to roughly 10% in propylene glycol, applied to the inner ear of New Zealand albino rabbits, three rabbits per assay, follicles scored for keratosis on a 0-5 scale whose own key reads 0-1 "not considered significant," 2-3 "borderline," 4-5 "considered positive." Read here off a 400dpi render of the journal scan rather than through a list quoting it. Cited for two things: an absence — its 220 rows contain no salicylic acid entry — and a near-miss. Its one salicylate row, "Octyl salicylate" at 0, sits in the sunscreen block just after octyl methoxycinnamate and is 2-ethylhexyl salicylate (octisalate), a UVB filter, not this acid. It supports no rating of salicylic acid in either direction.
- Morris WE, Kwan SC. "Use of the rabbit ear model in evaluating the comedogenic potential of cosmetic ingredients." J Soc Cosmet Chem 34:215-225 (1983) An independent laboratory's rabbit ear-canal assay on the same 0-5 scale, three rabbits, materials applied undiluted unless stated, 14 applications, graded microscopically. It predates Fulton 1989 and contradicts it in print on several materials, so it is not a republisher of him. Its 32 test materials are seven lanolins, nine vegetable oils, eleven esters and five surfactants. Cited for an absence: salicylic acid is not among them.
- Reynolds RV, Yeung H, Cheng CE, et al. "Guidelines of care for the management of acne vulgaris." J Am Acad Dermatol 90(5):1006.e1-1006.e30 (2024). PMID 38300170 The American Academy of Dermatology's clinical practice guideline, developed with GRADE methodology. Cited for one thing: it conditionally recommends topical salicylic acid for acne, and notes the OTC form at 0.5% to 2%. This is a recommendation to APPLY the ingredient to acne-prone skin — a strong proxy for non-comedogenicity, and a checkable one — but it is a treatment guideline, not a comedogenicity assay. Its own text records the recommendation as conditional rather than strong. It counts no comedones and measures no comedone induction.
- Arif T. "Salicylic acid as a peeling agent: a comprehensive review." Clin Cosmet Investig Dermatol 8:455-461 (2015). PMID 26347269 A peer-reviewed narrative review of salicylic acid as a keratolytic and peeling agent. Cited for mechanism only: it describes salicylic acid as lipophilic, penetrating the sebaceous follicle, and acting as a keratolytic and desmolytic agent that loosens corneocyte junctions — an action directed at clearing follicular plugging rather than causing it. It is a review of therapeutic use, not a comedogenicity measurement, and describing what an ingredient does to existing keratin is not the same as testing whether it induces comedones.
- "Comedogenicity in cosmeceuticals: a review of clinical relevance, regulatory gaps, and future directions." JAAD Reviews (2025) A recent peer-reviewed review of the comedogenicity field from 1972 onward. It is a synthesis of the legacy literature, not a new measurement, and independent of Fulton only in authorship. Cited for one field-wide caveat: no standardised comedogenicity test exists, and "non-comedogenic" is an unregulated label. It sets the ceiling on how much any comedogenic number, present or absent, can be asked to carry.
- Consumer comedogenic checkers and ingredient databases (CosDNA and similar) Aggregators that publish a 0-5 "acne" number per ingredient with no disclosed method, provenance or citation. Salicylic acid is listed at 0 on scale pages of this kind. Cited as the artefact being addressed, not as a measurement: we traced no primary assay behind that 0 and we make no claim about who entered it or why. It is not carried as our legacy value.
Others in the same family
Actives behave similarly enough that the evidence for one is often wrongly read across to the others. These are its structural relatives, not a guess. What the evidence says about actives as a family ›
Last reviewed 2026-08-12 · How we decide